Antibacterial agents, their preparation and use

ABSTRACT

A monocyclic β-lactam antibiotic having a formamido substituent at the 3S-position, including compounds of the formula (I): ##STR1## and salts thereof wherein R is --SO 3  H; --PO(OH)Y wherein Y is C 1-6  alkoxy, hydroxy, aryloxy, C 1-6  alkyl or aryl; ##STR2## wherein Z represents C 1-6  alkyl or aryl; ##STR3## wherein Z 1  and Z 2  may be the same or different and each represents hydrogen, C 1-6  alkyl, aryl, amino or C 1-6  alkoxy, or Z 1  and Z 2  together form the residue of a heterocyclic ring; --OSO 3  H; or ##STR4## where X is hydrogen or hydroxy; R 1  is an amino, protected amino or carboxylic acylamino group, and R 2  and R 3  are independently selected from hydrogen or a hydrocarbon group of 1 to 18 carbon atoms.

This invention relates to β-lactam containing antibacterial agents andin particular to a class of monocyclic β-lactams having a 3S-formamidosubstituent. This invention further relates to processes for preparingsuch compounds and to compositions containing them. These compounds areof use in the treatment of bacterial infection in animals, for examplemammals such as man.

The present invention provides a monocyclic β-lactam antibiotic having aformamido substituent at the 3S-position. Suitably the monocyclicβ-lactam antibiotic is substituted at the 3R-position by an acylaminogroup.

Suitably the present invention provides the compounds of the formula(I): ##STR5## and salts thereof wherein R is --SO₃ H; --PO(OH)Y whereinY is C₁₋₆ alkoxy, hydroxy, aryloxy, C₁₋₆ alkyl or aryl; ##STR6## whereinZ represents C₁₋₆ alkyl or aryl, ##STR7## wherein Z¹ and Z² may be thesame or different and each represents hydrogen, C₁₋₆ alkyl, aryl, aminoor C₁₋₆ alkoxy, or Z¹ and Z² together form the residue of a heterocyclicring; --OSO₃ H; or ##STR8## where X is hydrogen or hydroxy; R¹ is anamino, protected amino or carboxylic acylamino group, and R² and R³ areindependently selected from hydrogen or a hydrocarbon group of 1 to 18carbon atoms.

Preferably R is --SO₃ H.

Suitably R¹ is a carboxylic acylamino group such as found inantibacterially active penicillins or cephalosporins. Thus suitablegroups R¹ include those of the sub-formulae (a), (b), (c), (d) and (e):##STR9## wherein n is zero, one or two, m is zero, one or two; A₁ isC₁₋₆ alkyl, C₃₋₆ cycloalkyl, C₄₋₇ cycloalkenyl, cyclohexadienyl, aryl orheteroaryl such as phenyl, substituted phenyl such as hydroxyphenyl,thienyl or pyridyl; X is a hydrogen, bromine or chlorine atom, or acarboxylic acid, carboxylate ester, sulphonic acid, tetrazolyl, azido,hydroxy, acyloxy, amino, acylamino, heterocyclylamino, ureido, guanidinoor acylureido; A₂ is an aromatic group such as phenyl,2,6-dimethoxyphenyl, 2-alkoxy-1-naphthyl, 3-arylisoxazolyl, isothiazolylor 3-aryl-5-methylisoxazolyl group; X₁ is a CH₂ OCH₂, CH₂ SCH₂ or(CH₂)_(n) group; X₂ is an oxygen or sulphur atom; A₃ is an aryl orheteroaryl group such as phenyl, substituted phenyl or aminothiazolyl;and A₄ is hydrogen, C₁₋₆ alkyl, C₃₋₆ cycloalkyl, arylaminocarbonyl, C₁₋₆alkylaminocarbonyl, C₁₋₆ alkanoyl, C₁₋₆ alkoxycarbonyl, C₂₋₆ alkenyl,carboxy C₁₋₆ alkyl, C₁₋₆ alkylsulphonyl and di-C₁₋₆alkylphosphatomethyl.

More suitably R¹ includes groups of the sub-formulae (f) and (g):##STR10## wherein R⁴ is a phenyl, thienyl or phenoxy group; R⁵ is ahydrogen atom or methyl group; R⁶ is a phenyl, p-hydroxyphenyl,cyclohexadienyl, or a 5- or 6-membered heteroaryl or heterocyclyl groupcontaining one to three heteroatoms selected from sulphur, oxygen ornitrogen, said group being optionally substituted by one, two or threesubstituents selected from hydroxy, amino, halo and C₁₋₆ alkoxy; and R⁷is a hydroxy, amino or carboxylic acid group or a phenyl, methylphenyl,indanyl or C₁₋₆ alkyl ester thereof, or is amino, ureido, acylamino oracylureido.

Examples of suitable groups R⁶ include thienyl, pyridyl, phenyl,p-hydroxyphenyl and aminothiazolyl.

A particularly preferred group of the sub-formula (f) is thephenoxyacetamido group. Another particularly preferred group of thesub-formula (f) is the phenylacetamido group.

Suitably the ureido group in either the sub-formula (c) or sub-formula(g) is of the formula --NH--CO--NR8R9 wherein R8 is a hydrogen atom or aC₁₋₆ alkyl group and R9 is an organic group, or R8 and R⁹ together withthe nitrogen atom to which they are joined form an optionallysubstituted heteroaryl or heterocyclyl ring containing 1 or 2 nitrogenatoms.

Suitably R⁹ is C₁₋₆ alkyl or an optionally substituted 5- or 6-memberedheteroaryl or heterocyclyl group containing one or two nitrogen atoms.

Suitable substituents for R⁹ and for the rings formed by R⁸ and R⁹together include one, two or three groups selected from C₁₋₆ alkyl, C₂₋₆alkenyl, C₂₋₆ alkynyl, C₃₋₆ cycloalkyl, optionally substituted phenyl,oxo, hydroxy optionally substituted such as C₁₋₆ alkoxy, C₂₋₆alkenyloxy, C₃₋₆ cycloalkyloxy or phenoxy, mercapto optionallysubstituted such as phenylthio or C₁₋₆ alkylthio; or amino orsubstituted amino such as C₁₋₆ alkylamino, optionally substitutedphenylamino, benzylamino or sulphonylamino for example C₁₋₆ alkylsulphonylamino or p-aminosulphonylphenylamino. Alternatively twosubstituents on the ring R⁹ or on the ring formed by R⁸ and R⁹ togethermay form the residue of a further carbocyclic or heterocyclic ring.

Suitably also X may be an acylamino or acylureido group, for example, ofthe sub-formula (h):

    --NH--CO--(NH--CO).sub.p --R.sup.10                        (h)

wherein p is zero or one and R¹⁰ is a hydrogen atom or an organic groupsuch as aryl, heteroaryl, heterocyclyl, C₂₋₆ alkenyl or C₁₋₆ alkyl.

Compounds of the formula (I) wherein R¹ is amino or protected amino haveantibacterial activity but are envisaged mainly as useful intermediatesin the preparation of compounds of the formula (I) wherein R¹ iscarboxylic acylamino. "Protected amino" means that the amino moiety (NH₂--) is protected in conventional manner by a group or groups that may beremoved under conventional conditions and would be suitable for use inthe processes of this invention. Examples of suitable protected aminogroups include hydrocarbyloxycarbonylamino such as t-butoxycarbonylaminoand benzyloxycarbonylamino; and benzylideneamino such as Ph--CH═N--.

Suitably in the compounds of the formula (I) R² is a hydrogen atom.Suitably also R³ is a hydrogen atom. Thus in a preferred aspect R² andR³ are each hydrogen.

Alternatively R² and R³ are independently selected from C₁₋₁₈hydrocarbons, for example C₁₋₆ alkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl, C₃₋₈cycloalkyl, aryl, aryl(C₁₋₆)alkyl, aryl(C₂₋₆)alkenyl, heterocyclyl andheterocyclyl (C₁₋₆)alkyl, any of such groups being optionallysubstituted. Suitably the above named heteroaryl and heterocyclyl ringscontain not more than 10 ring atoms, up to 4 of which are selected fromoxygen, sulphur and nitrogen.

One particularly preferred sub-group of compounds is that of the formula(II): ##STR11## and salts thereof wherein R and R⁶ are as hereinbeforedefined, R¹¹ and R¹² are independently selected from hydrogen, C₁₋₆alkyl, halo, amino, hydroxy or C₁₋₆ alkoxy, and R¹³ is hydrogen, C₁₋₆alkyl, or aralkyl such as benzyl. Suitably C₁₋₆ alkyl groups for thegroups R¹¹, R¹² and R¹³ include methyl, ethyl, n- and iso-propyl, and n,sec-, iso- and tert-butyl. Preferably R¹³ is ethyl. Preferably R¹¹ andR¹² are each hydrogen. Preferably R is --SO₃ H.

A further preferred sub-group of compounds is that of the formula (III):##STR12## and salts thereof wherein R is as hereinbefore defined and pis zero or one.

Preferably R is --SO₃ H or a salt thereof.

Another preferred sub-group of compounds is that of the formula (IV):##STR13## and salts thereof wherein R¹⁴ is a cation, hydrogen atom or abenzyl, phenyl, methylphenyl or indanyl group, and R and R⁶ are ashereinbefore defined.

Preferably R is --SO₃ H.

Yet another preferred sub-group of compounds is that of the formula (V):##STR14## and salts thereof wherein R and R⁶ are as defined hereinabove.

Preferably R is --SO₃ H.

Another class of preferred compounds is that of the formula (VI):##STR15## and salts thereof wherein R is as hereinbefore defined and R¹⁵is hydrogen, C₁₋₆ alkyl such as methyl and ethyl, C₁₋₆ alkanoyl such asformyl and acetyl, methoxy-carbonyl, ethenyl, methanesulphonyl,carboxy(C₁₋₆)alkyl such as carboxymethyl, carboxyethyl and2-carboxyprop-2-yl, or dimethylphosphatomethyl.

Preferably R is --SO₃ H.

The major utility of the compounds of the formulae (I)-(VI) and saltsthereof is as pharmaceuticals and accordingly the salts are preferablypharmaceutically acceptable. The compounds of this invention bothpharmaceutically acceptable and non-pharmaceutically acceptable may beused as intermediates, for example for the preparation ofpharmaceutically acceptable salts of this invention, or innon-pharmaceutical usage such as a disinfectant or paint additive.

Suitable pharmaceutically acceptable salts include metal salts such asalkali metal salts for example sodium and potassium, alkaline earthmetal salts such as calcium and magnesium, and ammonium and substitutedammonium salts, for example tetrabutylammonium and pyridinium.

In another aspect of this invention there is provided a pharmaceuticalcomposition which comprises a compound of the formula (I) or apharmaceutically acceptable salt thereof and a pharmaceuticallyacceptable carrier.

The composition may be formulated for administration by any route, suchas oral topical or parenteral. The compositions may be in the form oftablets, capsules, powders, granules, lozenges, creams or liquidpreparations, such as oral or sterile parenteral solutions orsuspensions.

Tablets and capsules for administration may be in unit dose presentationform, and may contain conventional excipients such as binding agents,for example syrup, acacia, gelatin, sorbitol, tragacanth, orpolyvinylpyrollidone: fillers, for example lactose, sugar, maize-starch,calcium phosphate, sorbitol or glycine, tabletting lubricants, forexample magnesium stearate, talc, polyethylene glycol or silica;disintegrants, for example potato starch; or acceptable wetting agentssuch as sodium lauryl sulphate. The tablets may be coated according tomethods well known in normal pharmaceutical practice. Oral liquidpreparations may be in the form of, for example, aqueous or oilysuspensions, solutions, emulsions, syrups or elixirs, or may bepresented as a dry product for reconstitution with water or othersuitable vehicle before use. Such liquid preparations may containconventional additives, such as suspending agents, for example sorbitol,methyl cellulose, glucose syrup, gelatin, hydroxyethyl cellulose,carboxymethyl cellulose, aluminium stearate gel or hydrogenated ediblefats, emulsifying agents, for example lecithin, sorbitan monooleate, oracacia; non-aqueous vehicles (which may include edible oils), forexample almond oil, oily esters such as glycerine, propylene glycol, orethyl alcohol; preservatives, for example methyl or propylp-hydroxybenzoate or sorbic acid, and, if desired, conventionalflavouring or colouring agents.

Suppositories will contain conventional suppository bases, e.g.cocoa-butter or other glyceride.

For parenteral administration, fluid unit dosage forms are preparedutilizing the compound and a sterile vehicle, water being preferred. Thecompound, depending on the vehicle and concentration used, can be eithersuspended or dissolved in the vehicle. In preparing solutions thecompound can be dissolved in water for injection and filter sterilisedbefore filling into a suitable vial or ampoule and sealing.Advantageously, agents such as a local anaesthetic, preservative andbuffering agents can be dissolved in the vehicle. To enhance thestability, the composition can be frozen after filling into the vial andthe water removed under vacuum. The dry lyophilized powder is thensealed in the vial and an accompanying vial of water for injection maybe supplied to reconstitute the liquid prior to use. Parentalsuspensions are prepared in substantially the same manner except thatthe compound is suspended in the vehicle instead of being dissolved andsterilization cannot be accomplished by filtration. The compound can besterilised by exposure to ethylene oxide before suspending in thesterile vehicle. Advantageously, a surfactant or wetting agent isincluded in the composition to facilitate uniform distribution of thecompound.

The compositions may contain from 0.1% by weight, preferably from 10-60%by weight, of the active material, depending on the method ofadministration. Where the composition comprise dosage units, each unitwill preferably contain from 50-500 mg of the active ingredient. Thedosage as employed for adult human treatment will preferably range from100 to 3000 mg per day, for instance 1500 mg per day depending on theroute and frequency of administration.

The compound of formula (I) in pharmaceutically acceptable form may bethe sole therapeutic agent in the compositions of the invention or acombination with other antibiotics or with a β-lactamase inhibitor maybe employed.

Suitable β-lactamase inhibitors include the compounds of the formula(VII) and pharmaceutically acceptable salts and esters thereof:##STR16## wherein A is hydroxy, substituted hydroxy, mercapto,substituted mercapto, amino, mono- or di-hydrocarbyl-substituted amino,or mono- or di-acylamino.

Further suitable β-lactamase inhibitors include penicillanic acid1,1-dioxide and salts and in-vivo hydrolysable esters thereof,6β-bromopenicillanic acid and salts and in-vivo hydrolysable esters and6β-iodopenicillanic acid and salts and in-vivo hydrolysable estersthereof.

Such compositions of this invention comprising a β-lactamase inhibitorare formulated in conventional manner.

The present invention further provides a process for the preparation ofa compound of the present invention which process comprises formulatinga monocyclic β-lactam having an amino substituted at the 3-position.

In another aspect the present invention provides a process for thepreparation of a compound of the formula (I) wherein R is a sulphonicacid group or salt thereof which process comprises the sulphonation of acompound of the formula (VIII): ##STR17## or reactive derivativethereof, wherein R¹, R² and R³ are as hereinbefore defined, andthereafter if necessary:

(i) converting a compound of the formula (I) wherein R¹ is amino orprotected amino to a compound of the formula (I) wherein R¹ iscarboxylic acylamino,

(ii) forming a pharmaceutically acceptable salt.

The sulphonation reaction may be conveniently performed using a sulphurtrioxide complex, examples of which include pyridine-sulphur trioxide,dimethylformamide-sulphur trioxide, trimethylamine-sulphur trioxide,lutidine-sulphur trioxide, dioxan-sulphur trioxide and chlorosulphonicacid-sulphur trioxide. A preferred reagent is pyridine-sulphur trioxide.

The sulphonation reaction is performed at a non-extreme temperature suchas 0°-80° C., more suitably 10°-50° C. and conveniently at ambienttemperature. Normally the reaction is performed in a solvent, forexample an organic solvent such as dimethylformamide, dichloromethane,chloroform, dioxan, tetrahydrofuran, or mixtures thereof. Of these thepreferred solvent is dioxan. reaction may lead to the preparation of aspecific salt of the β-lactam, for example where the reagent used ispyridine-sulphur trioxide, the salt formed is the pyridinium salt. Thismay be converted to any other desired salt using conventional methods ofion-replacement, for example using ion-exchange resin, ion-pairextraction, crystallisation and precipitation.

Compounds of the formula (I) wherein R¹ is protected amino may beconverted to compounds of the formula (I) wherein R¹ is carboxylicacylamino via the intermediacy of the compounds of the formula (I)wherein R¹ is amino.

Suitable amino-protecting groups include those known in the β-lactam artto be convertible to amino, for example hydrogenolysable groups, such asbenzyloxycarbonylamino.

Compounds of the formula (I) wherein R¹ is carboxylic acylamino may beprepared by the reaction of a compound of the formula (I) wherein R¹ isamino or a derivative thereof that permits N-acylation to take place,with an N-acylating derivative of a carboxylic acid of the formula (IX):

    R.sup.16 CO.sub.2 H                                        (IX)

wherein R¹⁶ is an organic group and any reactive group is optionallyprotected, and thereafter if necessary, removing any protecting group.

Suitable groups which permit acylation to take place and which areoptionally present on the amino group R¹ includes N-silyl, N-stannyl andN-phosphorus groups, for example trialkylsilyl groups such astrimethylsilyl, trialkyltin groups such as tri-n-butyl-tin, groups ofthe formula --PR^(a) R^(b) wherein R^(a) is an alkyl, alkoxy, haloalkyl,aryl, aralkyl, haloalkoxy, aryloxy, aralkyloxy or dialkylamino group,R^(b) is the same as R^(a) or is halogen or R^(a) and R^(b) togetherform a ring: suitable such phosphorus groups being --P(OC₂ H₅)₂, --P(C₂H₅)₂, ##STR18##

A reactive N-acylating derivative of the acid (IX) is employed in theabove process. Suitable N-acylating derivatives include an acid halide,preferably the acid chloride or bromide. Acylation with an acid halidemay be effected in the presence of an acid binding agent for examplemolecular sieve or a pyridine or a tertiary amine (such as triethylamineor dimethylaniline), an inorganic base (such as calcium carbonate orsodium bicarbonate) or an oxirane, which binds hydrogen halide liberatedin the acylation reaction. The oxirane is preferably a(C₁₋₆)-1,2-alkylene oxide--such as ethylene oxide or propylene oxide.The acylation reaction using an acid halide may be carried out at atemperature in the range -50° C. to +50° C., preferably -20° C. to +20°C., in aqueous or non-aqueous media such as aqueous acetone, ethylacetate, dimethylacetamide, dimethylformamide, acetonitrile,dichloromethane, 1,2-dichloroethane, or mixtures thereof.

Alternatively, the reaction may be carried out in an unstable emulsionof water-immiscible solvent, especially an aliphatic ester or ketone,such as methyl isobutyl ketone or butyl acetate.

The acid halide may be prepared by reacting the acid (IX) or a saltthereof with a halogenating (eg. chlorinating or brominating) agent suchas phosphorus pentachloride, thionyl chloride or oxalyl chloride.

Alternatively, the N-acylating derivative of the acid (IX) may be asymmetrical or mixed anhydride. Suitable mixed anhydrides arealkoxyformic anhydrides, or anhydrides with, for example carbonic acidmono-esters, trimethyl acetic acid, thioacetic acid, diphenylaceticacid, benzoic acid, phosphorus acids such as phosphoric or phosphorousacids, sulphuric acid or aliphatic or aromatic sulphonic acids such asp-toluenesulphonic acid. The mixed or symmetrical anhydrides may begenerated usingN-ethoxycarbonyl-2-ethoxyl-2-ethoxy-1,2-dihydroquinoline. When asymmetrical anhydride is employed, the reaction may be carried out inthe presence of 2,6-lutidine as catalyst.

Alternatively N-acylating derivatives of acid (IX) are the acid azide,or activated esters such as esters with 2-mercaptopyridine,2-mercaptothiazoline, cyanomethanol, p-nitrophenol, 2,4-dinitrophenol,thioalcohols such as thiophenol, methanethiol, ethanethiol andpropanethiol, halophenols, including pentachlorophenol, monomethoxy- orphenol or 8-hydroxyquinoline, N-hydroxysuccinimide or1-hydroxybenztriazole; or amides such as N-acylsaccharins orN-acylphthalimides; or an alkylidine iminoester prepared by reaction ofthe acid (IX) with an oxime.

Other reactive N-acylating derivatives of the acid (IX) include thereactive intermediate formed by reaction in situ with a condensing agentsuch as a carbodiimide, for example N,N-dimethyl-, dipropyl- ordiisopropylcarbodiimide, N,N'-di-cyclohexylcarbodiimide, orN-ethyl-N'-α-dimethylaminopropylcarbodiimide; a suitable carbonylcompound, for example N,N'-carbonyldiimidazole orN,N'-carbonylditriazole; an isoxazolinium salt, for exampleN-ethyl-5-phenylisoxazolinium-3-sulphonate orN-t-butyl-5-methylisoxazolinium perchlorate; or anN-alkoxycarbonyl-2-alkoxy-1,2-dihydroquinoline, such asN-ethoxycarbonylethoxy-1,2-dihydroquinoline. Other condensing agentsinclude Lewis acids (for example BBr₃ -C₆ H₆); or a phosphoric acidcondensing agent such as diethylphosphorylcyanide. The condensationreaction is preferably carried out in an organic reaction medium, forexample methylene chloride, dimethylformamide, acetonitrile, alcohol,benzene, dioxan or tetrahydrofuran.

In a further aspect the present invention provides a process for thepreparation of a compound of the formula (I) which process comprises theformylation of a compound of the formula (X): ##STR19## or salt thereofor derivative thereof that permits N-formylation to take place, whereinR, R² and R³ are as hereinbefore defined and any reactive groups may beprotected, and R¹⁷ is a carboxylic acylamino group or a protected aminogroup and thereafter if desired:

(i) converting a compound of the formula (I) wherein R¹ is not aminointo a compound of the formula (I) wherein R¹ is amino;

(ii) removing any protecting group on R;

(iii) forming a pharmaceutically acceptable salt.

Suitable formylating agents include mixed anhydrides such as formicacetic anhydride. The reaction may be suitably performed at a depressedtemperature such as -50° to +10° C. in an aprotic solvent, for exampledichloromethane, tetrahydrofuran, chloroform, dimethylformamide,hexamethylphosphoramide or dimethylsulphoxide. Suitably a tertiary baseis present such as a base of the pyridine type, for example pyridine,lutidine or picoline.

Compounds of the formula (VIII) may be prepared by the formylation of acompound of the formula (XI): ##STR20## or derivative thereof thatpermits N-formylation to take place, wherein R², R³ and R¹⁷ are ashereinbefore defined; and thereafter if desired, converting a compoundof the formula (VIII) wherein R¹ is not amino to a compound of theformula (VIII) wherein R¹ is amino.

Suitable methods of formylation are as described hereinabove withrespect to the compound of the formula (X).

It is preferred that the β-lactam nitrogen is in the form of --NH-- or asilyl derivative thereof.

Compounds of the formulae (X) and (XI) may be prepared by the reactionof a corresponding compound of the formula (XII): ##STR21## wherein R²⁰is carboxylic acylamino or protected amino such asbenzyloxycarbonylamino or t-butoxycarboxylamino, R² and R³ are ashereinbefore defined, R¹⁹ is hydrogen, a protecting group or a group Ror a salt thereof, and R¹⁸ is C₁₋₆ alkyl, aryl or benzyl; with anhydrousammonia in the presence of a metal ion such as mercury, silver,thallium, lead or copper.

Suitably R¹⁸ is C₁₋₆ alkyl such as a methyl, ethyl, n- or iso-propyl, orn-, sec-, iso- or tert-butyl group. A preferred alkyl group is methyl.

Suitably R¹⁸ is an aryl group such as phenyl optionally substituted byC₁₋₆ alkyl, C₁₋₆ alkoxy, halo or nitro. Preferably R¹⁸ is phenyl, o-, m-or p-methylphenyl, or o-, m- or p-nitrophenyl. A particularly preferredgroup R¹⁸ is p-methylphenyl.

Suitable solvents in which the reaction may be performed are aprotic forexample diethyl ether, tetrahydrofuran, dimethylformamido andhexamethylphosphoramide. Normally the reaction is performed under aninert atmosphere and at an ambient or depressed temperature such as-100° C. to +30° C. the course of the reaction may be followed byconventional methods such as thin layer chromatography and terminatedwhen an optimum quantity of desired product is present in the reactionmixture.

The preferred metal ion for use in this reaction is the mercuric ion,aptly in the form of mercuric acetate.

Alternatively compounds of the formulae (X) and (XI) may be prepared bythe reaction of a corresponding compound of the formula (XIII):##STR22## wherein R²⁰, R², R³ and R¹⁹ are as hereinbefore defined, Z ischloro or bromo and R²¹ is C₁₋₃ alkyl or benzyl; with a source ofammonia. The compounds of the formula (XIII) may be prepared by thereaction of a compound of the formula (XIV): ##STR23## wherein R²⁰, R²,R³, R₁₉ and R²¹ are as hereinbefore defined, with a halogenating agentsuch as chlorine in an inert solvent, for example dichloromethane, at adepressed temperature such as -80° C. to -30° C.

A preferred method of preparation of the compounds of the formulae (X)and (XI) comprises the reaction of a compound of the formula (XV):##STR24## wherein R², R³, R²⁰ and R¹⁹ are as hereinbefore defined, andR²² is a C₁₋₆ alkyl, aryl or benzyl group; with anhydrous ammonia or anamine of the formula (XVI):

    R.sup.23 --NH.sub.2                                        (XVI)

wherein R²³ is a removable protecting group such as benzyl; andthereafter if necessary removing any protecting group to form either thecompound of the formula (X) or (XI).

Suitably such a reaction is performed at a non-extreme temperature forexample 0° C.-60° C., normally 10° C.-40° C. and preferably ambient. Thereaction is conveniently performed in an aprotic solvent such astetrahydrofuran or dioxan.

The compounds of the formula (XV) may be prepared by the oxidation of acompound of the formula (XII) as hereinbefore defined. Such oxidationmay be conveniently performed in conventional manner, for example usinga per-acid such as peracetic acid or m-chloroperbenzoic acid, suitablyat an ambient or depressed temperature. Suitable solvents for such asulphoxidation include ethyl acetate, chloroform, dichloromethane,dioxan and tetrahydrofuran.

Examples of suitable protecting groups for the group R¹⁹ include thoseknown in the art as being cleavable to provide the --NH--. Mention maybe made of silyl groups such as trimethylsilyl,tertiarybutyldimethylsilyl, and tri-isopropylsilyl. A preferredprotecting group is (p-methoxymethoxy)phenyl which is removable bycerium ammonium nitrate. Other protecting groups of interest includethose cleavable by methanolysis such as --C(CO₂ R)═O (This moiety may bederived from groups of the type --C(CO₂ R)═(CH₃)₂). Further suitableprotecting groups include C₁₋₆ alkoxy and benzyloxy. A further suitableprotecting group is 2,4-dimethoxybenzyl which is removable withpotassium persulphate.

Compounds of the formula (XII) may be prepared by methods analogous tothose known for the preparation of 7-α-thiocephalosporins and6-α-thiopenicillins, from the compounds of the formula (XVII): ##STR25##wherein R², R³ and R¹⁹ are as hereinbefore defined and R²⁴ is anoptionally substituted aromatic ring. In such a reaction preferably R₁₉is (p-methoxymethoxy)phenyl or a group such as --C(CO₂ R)═O. If R¹⁹ issilyl then it is preferred to use a strong non-nucleophilic base such asdiazabicyclononene or diazabicycloundecene in a halogenated hydrocarbonfor example dichloromethane, and suitably use a reagent such as CH₃S--SO₂ --CH₃.

Suitably R²⁴ is p-nitrophenyl.

Compounds of the formula (XVII) may be prepared by reaction of acompound of the formula (XIX): ##STR26## wherein R², R³ and R¹⁹ are ashereinbefore defined, with a compound of the formula (XX):

    R.sup.24 --CHO                                             (XX)

wherein R²⁴ is as hereinbefore defined.

Such reaction is conveniently performed in an inert solvent such asbenzene toluene, dimethylformamide or acetonitrile, and may be conductedat ambient or an elevated temperature, for example 15° C. to 110° C.This reaction is an equilibrium reaction involving the formation ofwater, so the reaction is aided by removing the water during the courseof the reaction, for example by azeotropic distillation or by thepresence of a drying agent.

It should be realised that the group R¹ may be converted to anothergroup R¹ at any convenient stage of the overall process of thisinvention by for example the general methods of deprotection and/oracylation outlined previously in this specification. Similarly the --SO₃H moiety may be introduced at any convenient stage of the overallprocess by the general methods of sulphonation referred to previously.

The compounds of the formula (XIX) may be prepared for example by themethods disclosed and discussed in UK Patent Application Publication No.2071650A or the methods exemplified hereinafter which methods aresummarised by the following Schemes. ##STR27##

A preferred variant of Scheme 3 is that where the nitrogen atom isprotected as a phthalimido group (that is, Q--NH-- is replaced byphthalimido). This prevents by-products arising from the intramolecularcyclization of the side-chain --NH-- moiety.

For convenience we have only depicted one enatiomer of the monocyclicβ-lactams described herein (with the exception of compounds (17)-(20) inthe examples hereinafter). These enantiomers are believed to be the moreactive enantiomers. Resolution may be performed using conventionalmethods at any appropriate stage of the synthetic sequence.

EXAMPLE 1(DL)-2-Benzyloxycarbonylamino-3-hydroxy-N-p-methoxymethoxyphenylpropionamide (1) ##STR28##

(DL)-Benzyloxycarbonylserine (42.67 g) was dissolved in drytetrahydrofuran (300 ml) and p-methoxymethoxyaniline (27.54 g) added.The mixture was cooled to 0° C. and treated withdicyclohexylcarbodiimide (40.79 g) in dichloromethane (100 ml). Thesolution was warmed to room temperature and after 30 min the solid wasremoved and the filtrate evaporated. Trituration of the residue withether gave a white solid (1) (59.17 g) slightly contaminated withdicyclohexylurea, but sufficiently pure for the next stage of theprocess;

ν_(max) (Nujol) 3425, 3280, 1700, 1675 and 1660 cm⁻¹ ;

δ(CDCl₃) 3.38 (3H, s), 3.75 br (1H, s, becomes d, J 5.5 Hz on D₂ Oexch.), 4.34 (1H, m, becomes t, J 5.5 Hz on D₂ O exch.), 4.76 br (1H, s,exch. D₂ O), 5.07 (2H, s), 6.76 (1H, d, J 9 Hz, exch. D₂ O), 6.9 (2H, d,J 8 Hz), 7.3 (5H, s), 7.49 (1H, d, J 8 Hz) and 9.48 (1H, s, exch. D₂ O).

EXAMPLE 2[3RS]-3-Benzyloxycarbonylamino-1-(p-methoxymethoxyphenyl)-azetidin-2-one(2) ##STR29##

The amide (1) (4.94 g) was dissolved in dry tetrahydrofuran (150 ml) andthe solution cooled to 0° C. Triphenylphosphine (3.8 g) was added,followed by the dropwise addition of diethyl azodicarboxylate (2.53 g)in tetrahydrofuran (5 ml). The solution was warmed to room temperatureand after 15 min poured into ethyl acetate-water. The organic layer wasseparated, washed with brine, dried and evaporated. Chromatography onsilica using ethyl acetate/methylene dichloride mixtures gave materialwhich on recrystallisation from ethyl acetate-hexane provided in βlactam(2) (1.75 g), mp 153°-154° C.;

ν_(max) (CHCl₃) 3430, 1750 and 1730 cm⁻¹ ;

δ(CDCl₃) 3.44 (2H, s), 3.55 (1H, dd, J 5.5 and 3 Hz), 3.88 (1H, dd),4.91 (1H, m), 5.55 (1H, m) and 6.9-7.5 (10H, m).

EXAMPLE 3 (3RS)-3-Amino-1-(p-methoxymethoxyphenyl)azetidin-2-one (3)##STR30##

The lactam (2) (3.2 g) was dissolved in dry dioxan (100 ml) andhydrogenated over 10% palladium/charcoal (1.0 g) until the uptake ofhydrogen ceased. The mixture was filtered through Kieselguhr and thefiltrate was evaporated to give a white solid (3) (1.95 g);

ν_(max) (CHCl₃) 3365, 1738 cm⁻¹ ;

δ(CDCl₃) 1.74 (2H, s, exch. D₂ O), 3.31 (1H, d, J 6.5 and 3 Hz), 3.44(2H, s), 3.88 (1H, dd, J 6.5 and 6 Hz), 4.3 (1H, dd, J 6 and 3 Hz), 5.11(2H, s), 6.98 (2H, d, J 9 Hz) and 7.17 (2H, d, J 9 Hz).

EXAMPLE 4 (3RS)-1-(p-Methoxymethoxyphenyl)-3-phthalimido-acetidin-2-one(6) ##STR31##

N-Phthaloylserine (4)(13.38 g; ca 80% pure by nmr) andp-methoxymethoxyaniline (6.96 g) were dissolved in dichloromethane (120ml) and tetrahydrofuran (10 ml). The solution was then cooled to 0° C.and treated with dicyclohexylcarbodi-imide in dichloromethane (20 ml).The reaction mixture was allowed to warm to room temperature and after1.5 h the solid was removed and the filtrate evaporated. The crudeproduct (5) was sufficiently pure for the next step, and was dissolvedin dry tetrahydrofuran (300 ml) at 0° C. Triphenyl-phosphine (17.88 g)was added followed by the dropwise addition of diethyl azodicarboxylate(11.65 g) in tetrahydrofuran (30 ml). The reaction mixture was allowedto warm to room temperature and after 0.5 h the solvent was evaporatedoff and the residue chromatographed on silica to provide (6) as acrystalline solid (B 12 g), m.p. 156° C.; ν_(max) (Nujol), 1790 (weak),1740, 1720 cm⁻¹ ; δ(CDCl.sub. 3) 3.45 (3H, s), 4.0 (2H, d, J 5 Hz), 5.13(2H, s), 5.46 (1H, t, J 5 Hz), 7.01 (2H, d, J 9 Hz), 7.35 (2H, d, J 9Hz), and 7.65-7.95 (4H, m). (Found: C, 64.7; H, 4.5; N, 7.9. C₁₉ H₁₆ N₂O₅ requires C, 64.8; H, 4.5; N, 8.0%).

EXAMPLE 5 (3RS)-3-Amino-1-(p-methoxymethoxyphenyl)azetidin-2-one (3)##STR32##

The lactam (6) (7.04 g) was dissolved in chloroform (80 ml) andN-methylhydrazine (2.02 g) added. The solution was stored at roomtemperature in the dark for 66 hours. The precipitated solid wasfiltered off. The filtrate was evaporated and the residue trituratedwith ether to provide (3) (4.04 g), identical to that described inExample 3.

EXAMPLE 6(3RS)-1-pMethoxymethoxyphenyl-3-N-p-nitrobenzylideneamino-azetidin-2-one(7) ##STR33##

A solution of the amine (3) (2.64 g) and p-nitrobenzaldehyde (1.80 g) inan anhydrous mixture of toluene (100 ml) and dichloromethane (20 ml) wasstirred for 20 hours at room temperature over 4A molecular sieves. Thereaction mixture was then filtered and the filtrate evaporated todryness. The residue was recrystallised from ethyl acetate-hexane toafford the product (7) as pale yellow needles (3.7 g). m.p. 139°-140°ν_(max) (Nujol) 1740, 1630, 1515 and 1350 cm⁻¹ ;

δppm (CDCl₃) 3.46 (3H, s), 3.86 and 4.07 (2H, ABq, J 5.5 Hz, higherfield arm further coupled, d, J 2.1 Hz, lower field arm further coupled,d, J 5.4 Hz), 5.03 (1H, dd, J 5.4 and 2.1 Hz), 5.14 (2H, s), 7.03 and7.33 (4H, ABq, J 10 Hz), 7.93 and 8.26 (4H, d, J 9 Hz),8.62 (1H, s);(Found: C, 60.9; H, 4.9; N, 11.9; C₁₈ H₁₇ N₃ O₅ requires C, 60.8; H,4.8; N, 11.8%).

EXAMPLE 7(3RS)-1-(p-Methoxymethoxyphenyl)-3-methylthio-3-N-p-nitrobenzylideneamino-azetidin-2-one(8) ##STR34##

A solution of3RS-1-(p-methoxymethoxyphenyl)-3-N-p-nitrobenzylideneamino-azetidin-2-one(7) (5.50 g) in dry dimethylformamide (75 ml) under argon was cooled to0° C. and treated with anhydrous potassium carbonate (2.24 g). Themixture was stirred for 10 minutes, then treated with a solution ofmethyl methanethiosulphonate (2.05 g) in dry dimethylformamide (10 ml).The mixture was stirred at 0° C. for a 1/2 hour, then allowed to warm to20° C. After 4 hours the mixture was partitioned between water and ethylacetate. The organic phase was separated and retained. The aqueous phasewas extracted with a further portion of ethyl acetate. The combinedorganic extractes were washed with water (x3), then brine. The solutionwas dried (M_(g) SO₄), filtered and the solvent evaporated. The residuewas chromatographed on silica gel yielding an oil, which on triturationwith ether gave the product (8) as a yellow crystalline solid, (3.74 g),m.p. 89°-90° C.; ν_(max) (CHCl₃) 1750, 1630, 1510, 1345 cm⁻¹ ; δppm(CDCl₃) (90 MHz) 2.25 (s, 3H), 3.43 (s, 3H), 3.93 and 4.02 (ABq, 2H, J6.0 Hz), 5.10 (s, 2H), 7.00 (d, 2H, J 9.0 Hz), 7.30 (d, 2H, J 9.0 Hz),7.97 (d, 2H, J 9.0 Hz), 8.26 (d, 2H, J 9.0 Hz), 8.88 (s, 1H). (Found: C,56.9; H, 4.8; N, 10.3; s, 8.3. C₁₉ H₁₉ N₃ O₅ S requires C, 56.9; H, 4.7;N, 10.5; S, 8.0%).

EXAMPLE 8(3RS)-3-Amino-1-(p-methoxymethoxyphenyl)-3-methylthio-azetidin-2-one-p-toluenesulphonicacid salt (9) ##STR35##

(3RS)-1-(p-Methoxymethoxyphenyl)-3-methylthio-3-N-p-nitrobenzylideneamino-azetidin-2-one(8) (3.24 g) in acetone (75 ml) was treated with a solution of4-p-toluenesulphonic acid monohydrate (1.54 g) in acetone (30 ml). Thesolution was stirred vigorously. After 1/2 hour the precipitated saltwas filtered off, washed thoroughly with ethyl acetate, then dried invacuo, giving the product (9) (3.37 g). ν_(max) (KBr) 3415, 1745, 1515,and 1170 cm⁻¹ ; δppm (d₆ -DMSO) (90 MHz) 2.25 (s, 3H), 2.43 (s, 3H),3.33 (s, 3H), 4.00 (s, 2H), 5.15 (s, 2H), 6.9 to 7.6 (m, 8H).

EXAMPLE 9(3RS)-3-[D-2-(4-Ethyl-2,3-dioxopiperazin-1-yl-carboxamido)-2-phenylacetamido]-3-(p-methoxymethoxyphenyl)-3-methylthio-azetidin-2-one(10) ##STR36##

A solution of (9) (200 mg) in dry dichloromethane (10 ml), containingtriethylamine (51 mg) and ground activated 4A molecular sieves (600 mg)was cooled to 0° C. and treated dropwise with a solution of2-(4-ethyl-2,3-dioxopiperazin-1-yl-carboxamido)-2-phenylacetylchloride(184 mg) in dry dichloromethane. On completion of the addition thestirred mixture was allowed to warm to 20° C. After 2 h the mixture wasfiltered through Kieselguhr. The filtrate was washed successively withwater, dilute HCl, water, saturated aqueous NaHCO₃ water, and brine,then dried (MgSO₄), filtered and the filtrate evaporated. The residuewas chromatographed on silica gel to yield the product (10) (180 mg) asa ca:2:1 mixture of diastereoisomers at C(3). ν_(max) (CHCl₃) 3275,1755, 1710, 1690 cm⁻¹ ; δppm (CDCl₃) (250M Hz) 1.22 (t, 3H, J 6.6 Hz),2.03 (s, 2H), 2.27 (s, 1H), 3.46 and 3.48 (both s, together 3H), 3.49 to3.65 (m, 4H), 3.72 to 4.22 (m, 4H), 5.13 and 5.14 (both s, together 2H),5.50 and 5.52 (both d, together 1H, both J 6.6 Hz), 6.95 to 7.55 (m,10H), 9.88 (d, 1/3H, J 6.6 Hz), 9.96 (d, 2/3 H, J 6.6 Hz).

EXAMPLE 10(3RS)-3-[D-2-(4-Ethyl-2,3-dioxopiperazin-1-yl-carboxamido)-2-phenylacetamido]-3-methylthio-azetidin-2-one(11) ##STR37##

A solution of (10) (100 mg) in tetrahydrofuran 2 ml) at 0° C. wastreated with ammonium ceric nitrate (CAN) (289 mg) in water (1 ml). Thesolution was stirred at 0° C. for 15 minutes. The cooling bath wasremoved and the solution treated with sodium sulphite to discharge theorange colour. The solution was poured into a vigorously stirred mixtureof saturated aqueous NaHCO₃ and dichloromethane. The mixture wasfiltered through Kieselguhr. The organic phase of the filtrate wasseparated and washed with water and brine, then dried (MgSO₄), filteredand the solvent evaporated off. Chromatography of the residue on silicagel gave the product (11) (49 mg), as a white solid; a mixture ofdiastereoisomers at C(3) partially separable by chromatography. ν_(max)(CHCl₃) 3280, 1765, 1715, and 1690 cm⁻¹ ;

DIASTEREOISOMER I; δppm (CD₃ OD) (250 MHz) 1.20 (t, 3H, J 6.6 Hz), 2.21(s, 3H), 3.34 and 3.63 (ABq, together 2H, J 6.6 Hz), 3.52 (q, 2H, J 6.6Hz), 3.59 to 3.68 (m, 2H), 3.93 to 4.14 (m, 2H), 5.51 (s, 1H), and 7.28to 7.52 (m, 5H).

DIASTEREOISOMER II; δppm (CD₃ OD) (250 MHz) 1.20 (t, 3H, J 6.6 Hz), 2.01(s, 3H), 3.34 and 3.67 (ABq, together 2H, J 6.6 Hz), 3.51 (q, 2H, J 6.6Hz), 3.58 to 3.67 (m, 2H), 3.91 to 4.12 (m, 2H), 5.51 (s, 1H), and 7.30to 7.53 (m, 5H).

EXAMPLE 11(3RS)-3-[D-2-(4-Ethyl-2,3-dioxopiperazin-1-yl-carboxamido)-2-phenylacetamido]-3-methylsulphinyl-azetidin-2-one(12) ##STR38##

A solution of (11) (514 mg) in dry dioxan (35 ml) was treated with asolution of peracetic acid in glacial acetic acid (2.51 ml of a 5.0% w/vsolution). The mixture was stirred at 20° C. for 20 min, then evaporatedto dryness. The residue was evaporated twice more from dry dioxan beforedrying thoroughly in-vacuo. The crude product (12) (3:5 ratio ofdiastereoisomers at C-(3)) was used without any further purification.

ν_(max) (CHCl₃) 3275, 1780, 1715 and 1690 cm⁻¹ ; δppm (CDCl₃) (250 MHz)1.20 (t, 3H, J 6.9 Hz), 2.43 (s, 3/8 3H), 2.61 (s, 5/8 3H), 3.40 to 3.62(m, 4H), 3.80 to 3.95 (m, 2H), 3.95 to 4.15 (m, 2H), 5.55 (d, 5/8H, J7.0 Hz), 5.59 (d, 3/8H, J 7.0 Hz), 6.90 (s, 3/8 H), 6.95 (s, 5/8H), 7.30to 7.55 (m, 5H), 7.77 (s, 3/8H), 8.02 (s, 5/8H), and 9.89 and 9.92 (bothd, together 1H, both J 7.0 Hz).

EXAMPLE 12(3RS)-3-Amino-3-[D-2-(4-ethyl-2,3-dioxopiperazin-1-yl-carboxamido)-2-phenylacetamido]-azetidin-2-one(13) ##STR39##

The sulphoxide (12) (489 mg) [the product of example 11] was suspendedin dry tetrahydrofuran (25 ml), and dry dioxan was added to obtain asolution. The flask was fitted with a septum cap and then partiallyevacuated. Ammonia gas (54 ml) was injected into the flask. The mixturewas stirred over night. The mixture was evaporated to dryness and theresidue dried in vacuo. Chromatography of the residue on silica gelyielded the product (13), (377 mg) as a white amorphous solid, beingapproximately a 2:3 ratio of diastereoisomers at C(3).

ν_(max) (CHCl₃) 3290, 1770, 1720, and 1690 cm⁻¹ ; δppm ((CD₃)₂ CO) (250MHz) 1.17 (t, 3H, J 6.6 Hz), 2.51 and 2.57 (both broad s, together 2H,exchange D₂ O), 3.29 and 3.56 (ABq, minor isomer, J˜5.0 Hz), 3.34 and3.44 (ABq, major isomer, J˜5.0 Hz), 3.50 (q, 2H, J˜6.6 Hz, collapses tos on irradiation at 1.17), 3.63 to 3.79 (m, 2H), 3.93 to 4.15 (m, 2H),5.60 (major isomer) and 5.62 (minor isomer) both d, together 1H, bothJ˜8.8 Hz, both collapse to s on D₂ O exchange), 7.17 (s, 3/5 H, exchangeD₂ O), 7.22 (s, 2/5 H, exchange D₂ O), 7.27 to 7.57 (m, 5 H), 8.16 (s,2/5 H, exchange D₂ O), 8.29 (s, 3/5 H, exchange D₂ O), and 9.96 (d, 1H,J˜8.8 Hz, exchange D₂ O).

EXAMPLE 13(3RS)-3-[D-2-(4-Ethyl-2,3-dioxopiperazin-1yl-carboxamido)-2-phenylacetamido]-3-formamido-azetidin-2-one(14) ##STR40##

A solution of (13) (219 mg) in dry dichloromethane (4ml) containingpyridine (95 mg) at 0° C. was treated with formic-acetic anhydride (53mg). After 30 mins at 0° C. the mixture was diluted with dry dioxan (5ml). The solvent was evaporated off and the residue evaporated once morefrom dry dioxan, finally drying the residue in vacuo. Chromatography ofthe residue on silica gel yielded the product (14) as a white foam(quantitative), which was a mixture of diastereoisomers at C-(3).

ν_(max) (CHCl₃) 3275, 1775, 1715 and 1690 cm-1; δppm ((CD₃)₂ CO) (250MHz) 1.18 (t, 3H, J 6.0 Hz), 3.51 (q, 2H, J˜6.0 Hz), 3.57 to 3.82 (m,4H), 3.95 to 4.15 (m, 2H), 5.64 (minor isomer) and 5.66 (major isomer)(both d, together 1H, both J˜7.8 Hz, both collapse to s on D₂ Oexchange), 7.26 to 7.67 (m, 6H, becomes m, 5H on D₂ O exchange) 8.05 to8.95 (m, 3H, becomes m, 1H at 8.06 to 8.49 on D₂ O exchange) and, 9.94(minor isomer) and 9.97 (major isomer) (both d, together 1H, both J˜7.8Hz, both exchange D₂ O).

EXAMPLE 14(3RS)-Potassium-3-[D-2-(4-Ethyl-2,3-dioxopiperazin-1-yl-carboxamido)-2-phenylacetamido]-3-formamido-2oxoazetidine-1-sulphonate(15) ##STR41##

A solution of (14) (29 mg) is dry dioxan (1 ml) was treated with sulphurtrioxide-pyridine complex (22 mg). The mixture was allowed to stand atroom temperature for 4 days. The mixture was diluted with anhydrousether and the precipitated solid triturated with anhydrous ether (x2).The solid was air dried, taken up in water and passed down a column ofAmberlite IR-120 (K⁺) ion exchange resin followed by chromatography onHP20-SS to give the product, (15), as a solid (4 mg) which was a 4:5ratio of diastereoisomers at C-(3).

ν_(max) (KBr) 3280, 1770, 1710, 1675, 1250, and 1050 cm⁻¹ ; δppm (D₂ O)(250 MHz) 1.18 (t, 3H, J 6.6 Hz), 3.50 (q, 2H, J 6.6 Hz), 3.60 to 3.80(m, 2H), 3.90 to 4.12 (m, 4H), 5.48 (s, 1H), 7.47 (broad s, 5H), 8.07(s, 4/9H), and 8.10 (s, 5/9H).

EXAMPLE 15 (3RS)-Potassium3-[D-2-(4-Ethyl-2,3-dioxopiperazin-1-ylcarboxamido)-2-pheylacetamido]-3-methylthio-2-oxo-azetidine-1-sulphonate(16) ##STR42##

A solution of (11) (50 mg) in dry dimethylformamide (0.5 ml) under aninert dry atmoshphere was treated with pyridine-sulphur trioxide complex(37 mg). After 4 days at 20° C., ether (˜4 ml) was added. The depositedsolid was triturated twice with anhydrous ether then air dried. Thesolid was taken up in water and passed down a column of Amberlite IR 120(K⁺) ion exchange resin. Chromatography on HP20 SS, and evaporation ofthe relevant fractions yielded the product (16), 25 mg, as a white solidbeing a 2:1 mixture of diastereoisomers at C-(3).

ν_(max) (KBr) 3290, 1765, 1710, 1675, 1245, and 1050 cm⁻¹ ; δppm (D₂ O)(250 MHz) 1.17 (t, 3H, J 7.1 Hz), 2.06 (s,2H), 2.10 (s, 1H), 3.50 (q,2H, J 7.1 Hz, collapse to s on irradiation at 1.17), 3.60 to 3.80 (m,3H), 3.90 to 4.13 (m, 3H), 5.48 (minor isomer) and 5.50 (major isomer)(both s, together 1H), and 7.47 (broad s, 5H).

EXAMPLE 16 (3S)-3-Triphenylmethylaminoazetidin-2-one (18) ##STR43##

The sulphone (17) (20.3 g) (E G Brain et al. J C S Perkin Trans 1. 1976,p447) was dissolved in tetrahydrofuran (200 ml), cooled to 0° C. underargon and sodium borohydride (3.8 g) in water (36 ml) added in fourportions over 10 mins. The reaction was removed from the cooling bath,allowed to warm to room temperature over 1.5 hour and glacial aceticacid (5.72 ml) added. After 15 mins the solution was diluted with ethylacetate (600 ml), washed with water (×2), saturated sodiumhydrogencarbonate solution, brine, dried (MgSO₄) and evaporated.Chromatography on silica gel gave the product (17) as a whitecrystalline solid (14.3 g). m.p. 103°-105° (toluene); [α]²³ D-51.2° (c lCHCl₃); ν_(max) (Nujol) 3340, 3250, 1760, 1730 cm⁻¹ ; δppm (CDCl₃) 2.14(1H, dd, J 5.9+ 2.4 Hz), 2.53 (1H, d, J 10.8 Hz, exchange), 2.63 (1H,dd, J 5.9 and 4.7 Hz), 4.21 (1H, broad s, collapses to dd, J 4.7 and 2.4Hz on exchange), 5.53 (1H, broad s, exchange), 7.2-7.6 (15H, m). (Found:C, 81.3; H, 6.2; N, 7.8; C₂₂ H₂₀ N₂ O. 1/3C₇ H₈ requires C, 81.5; H,6.3; N, 7.8%).

EXAMPLE 17(3S)-1-t-Butyldimethylsilyl-3-triphenylmethylamino-azetidin-2-one (19)##STR44##

The azetidinone (328 mg) was dissolved in dry dimethylformamide (3 ml)containing t-butyldimethylchlorosilane (166 mg) at 0° C. andtriethylamine (0.154 ml) in dry dimethylformamide (0.5 ml) added over 1min. After 15 mins at 0° C. and warming to room temperature, thereaction diluted with ethyl acetate, washed with water, very dilutehydrochloric acid, brine, dried (MgSO₄) and evaporated. Chromatographyon silica gel afforded the product (19) as a white crystalline solid(338 mg). m.p. 166° (hexane); [α]¹⁹ D-56°; (c2 in CHCl₃) ν_(max) (KBr)3460, 1745 cm⁻¹ ; δppm (CDCl₃) 0.11 (6H, s), 0.86 (9H, s), 2.21 and 2.60(2H, ABq, d, J 6 Hz, higher field arm further coupled, d, J 2.5 Hz,lower field arm further coupled, d, J 5 Hz), 2.5-2.8 (1H, broad s,exchange), 4.20 (1H, m), 7.1-7.6 (15H, m). (Found: C, 76.1; H, 7.5; N,6.3; C₂₈ H₃₄ N₂ OSi requires C, 76.0; H, 7.7; N, 6.3%).

EXAMPLE 18 (3S)-3-Amino-1-t-butyldimethylsilyl azetidin-2-one (20)##STR45##

The β-lactam (277 mg) was dissolved in anhydrous dichloromethane (4 ml),cooled to 0° C. and p-toluenesulphonic acid monohydrate (119 mg) in theminimum volume of methanol was added. After 17 hours at 5° C.,triethylamine (0.1 ml) was added and after 10 mins the solvent wasevaporated off. Chromatography on silica gel afforded the amine (20) asa solid (66 mg) ν_(max) (CHCl₃) 3375, 1730 cm⁻¹ ; δppm (CDCl₃) 0.23 (6H,s), 0.95 (9H, s), 1.74 (2H, s, exchange) 2.97 (1H, dd, J 6.3 and 3 Hz),3.51 (1H, dd, J 6.3 and 6 Hz), 4.24 (1H, dd, J 6 and 3 Hz). (Found: M⁺--H, 199.1281, C₉ H₁₉ N₂ OSi requires M--H⁷ 199.1301).

EXAMPLE 19 (3S)-1-t-Butyldimethylsilyl-3-N-p-nitrobenzylideneaminoazetidin-2-one (21) ##STR46##

The amine (20) (2.096 g) was dissolved in toluene (50 ml) andp-nitrobenzaldehyde (1.58 g) added. The solution was vigorously stirredfor 18 hours in the presence of 3A molecular sieves. The mixture wasfiltered through Kieselguhr and the filtrate evaporated. The residueslowly crystallised and was recrystallised from hexane to provide (21)(3.26 g); [α]¹⁹ D-205° (c 0.8 in CHCl₃) ν_(max) (CHCl₃) 1740, 1635,1520, and 1350 cm⁻¹ ; δ(CDCl₃) 0.99 (9H, s), 3.47 (1H, dd, J 6.5 and 3Hz), 3.68 (1H, dd, J 6.5 and 6 Hz), 5.0 (1H, m), 7.92 (2H, s, J 8 Hz),8.28 (2H, s, J 8 Hz), and 8.55 (1H, slightly broadened s, J ca 0.5 Hz).

EXAMPLE 201-t-Butyldimethylsilyl-3-methylthio-3-N-p-nitrobenzylideneamino-azetidin-2-one(22) ##STR47##

The Schiff base (21) (2.07 g) was dissolved in dry dichloromethane (45ml) and methylmethanethiosulphonate (861 mg) added in dichloromethane (2ml), followed by 1,5-diazabicyclo[5.4.0]undec-5-ene (1.08 g) indichloromethane (3 ml). After 30 mins the solution was washed withaqueous ammonium chloride (×3), brine, dried, and evaporated.Chromatography on silica eluting with dichloromethane-hexane mixturesafforded the product (22) (1.33 g). m.p. 127°-128° C. ν_(max) (CHCl₃)1735, 1625, 1525, and 1350 cm⁻¹ ; δ(CDCl₃) 0.25 (3H, s), 0.28 (3H, s),0.98 (9H, s), 2.18 (3H, s), 3.58 (2H, ABq, J 7 Hz), 7.97 (2H, d, J 9Hz), 8.25 (2H, d, J 9 Hz), and 8.8 (1H, s).

EXAMPLE 21(3RS)-3-Amino-1-t-butyldimethylsilyl-3-methylthio-azetidin-2-one-p-toluenesulphonicacid salt (23)

A solution of (22) (3.32 g) in ethyl acetate (65 ml) was treated withp-toluenesulphonic acid monohydrate (1.66 g) in a minimum volume ofethyl acetate. After 15 mins the precipitate was filtered off, washedwith ethyl acetate then ether and dried in vacuo, giving the product(23) (3.57 g).

ν_(max) (nujol) 3160, 1720 and 1170 cm⁻¹ ; δppm ((CD₃)SO) (60 MHZ)0.20(S, 3H), 0.25 (s, 3H) 0.95 (S, 9H), 2.30 (S, 3H), 2.35 (S, 3H), 3.45and 3.65 (ABq, 2H, J 7 Hz), 7.15 and 7.55 (ABq, 4H, J 8 Hz), 9.35 (Broads, approx. 3H, exch). (Found: C, 48.91; H, 6.96; N, 6.80; S, 15.43. C₁₇H₃₀ N₂ O₄ SiS₂ requires C, 48.77; H, 7.22; N, 6.69; S, 15.32).

EXAMPLE 22(3RS)-1-t-Butyldimethylsilyl-3-methylthio-3-phenoxyacetamido-azetidin-2-one(24)

A suspension of (23) (830)mg) in dry dichloromethane (20 ml) at -10° C.was treated with triethylamine (220 mg) and pyridine (172 mg), followedby a solution of phenoxyacetyl chloride (372 mg) in dry dichloromethane(˜4 ml). The mixture was washed with very dilute HCl, followed by brine.The organic phase was dried and the solvent evaporated. Chromatographyon silica yet gave the product (24) (730 mg). ν_(max) (CHCL₃) 3400,1745, and 1690 cm⁻¹ ; δppm (CDCl₃) (90 MHz) 0.25 and 0.27 (boths,together 6H), 0.98 (S, 9H), 2.22 (S, 3H), 3.36 and 3.81 (ABq, 2H, J 7.0Hz), 4.50 (S, 2H), 6.80 to 7.50 (m, 6H).

EXAMPLE 23 (3RS)-3-Methylthio-3-phenoxyacetamido-azetidin-2-one (25)

A solution of (24) (516 mg) in dry tetrahydrofuran (THF) (10 ml) wascooled to -10° C. and treated with tetrabutylammonium fluoride (476 mg)and glacial acetic acid (180 mg) in a minimum volume of dry THF. Afterapproximately 15 mins the mixture was poured into a mixture of ethylacetate and water. The organic phase was separated and washedsuccessively with dilute sodium bicarbonate, dilute hydrochloric acid,and brine, then dried and evaporated.

Chromatography on silica gel gave the product (25) (366 mg), a whitesolid. ν_(max) 3410, 1775 and 1690 cm⁻¹ ; δppm (CDCl₃) (90 MHz) 2.24 (s,3H), 3.48 and 3.90 (ABq, 2H, J 7.0 Hz), 4.50 (s, 2H), 6.24 (s, 1H,exch.), 6.80 to 7.45 (m, 6H, becomes m, 5H, on exch.)

EXAMPLE 24 (3RS)-3-Methylsulphinyl-3-phenoxyacetamido-azetidin-2-one(26)

A solution of (25) (175 mg) in dry dioxan (7 ml) was treated with asolution of peracetic acid in glacial acetic acid (0.99 ml of a 5.07 %w/v solution). The mixture was stirred at room temperature forapproximately 20 mins, then evaporated to dryness. The residue wasevaporated once more from dry dioxan before drying thoroughly in vacuo.The residue was taken up in chloroform and chromatographed on a shortcolumn of silica gel eluting with 10% meOH/CHCl₃ to give the product(26) (186 mg) a mixture of sulphoxide isomers (approximately 1:2)ν_(max) (CHCl₃) 3410, 1785, 1690, and 1490 cm⁻¹ ; δppm (CDCl₃) (90 MHz)2.60 (major isomer) and 2.67 (minor isomer) (both s, together 3H), 3.79and 4.12 (ABq, minor isomer, J 8 Hz) and 3.87 and 4.01 (ABq, majorisomer, J 6 Hz) (together 2H), 4.53 (minor isomer) and 4.60 (majorisomer) both s, together 2H), 6.52 (s, 1H, exch.), 6.80 to 7.45 (m, 5H),7.78 (s, 1H, exch.).

EXAMPLE 25 (3RS)-3-Amino-3-phenoxyacetamido-azetidin-2-one (27)

The sulphoxide (26) (186 mg) in dry tetrahydrofuran (6 ml) was treatedwith dry ammonia gas (14.8 ml) and the mixture stirred at roomtemperature for 3 days. The solvent was evaporated and the residuechromatographed on silica gel to give the product, (27) (113 mg).

Ξmax (CHCl₃) 3405, 3290, 1775, and 1680 cm⁻¹ ; δppm (CDCl₃) (90 MHz)2.29 (s, 2H, exch.), 3.49 and 3.73 (ABq, 2H, J 6 Hz), 4.43 (S, 2H), 6.34(S, 1H, exch.), 6.8 to 7.4 (m, 5H), 7.41 (S, 1H, exch.)

EXAMPLE 26 (3RS)-3-Formamido-3-phenoxyacetamido-azetidin-2-one (28)

The amine (27) (66 mg) in dry dichloromethane (5 ml) was cooled to 0°and treated with pyridine (49 mg) followed by formic-acetic anhydride(27 mg). The mixture was stirred at 0° for 15 minutes then allowed towarm to room temperature over 15 minutes, and evaporated to dryness. Theresidue was chromatographed on silica gel to give the product (28) (53mg).

ν_(max) (KBr) 3240, 1765, 1690 and 1660 cm⁻¹ ; δppm ((CD₃)₂ CO) (250MHz) 3.81 (s, 2H), 4.57 (s, 2H), 6.90 to 7.05 (m, 3H), 7.25 to 7.37 (m,2H), 7.40 and 7.62 (both broad s, together 1H, exch.) 7.85 to 8.60 (m,3H, exch. to give m, 1H).

EXAMPLE 27 (3RS)-Potassium3-Formamido-3-phenoxyacetamido-2-oxo-azetidine-1-sulphonate (29)

The β-lactam (28) (50 mg) was dissolved in warm dry dioxan (3 ml). Thesolution was treated with pyridine-sulphur trioxide complex (61 mg) atroom temperature and stirred for approximately 72 hours. The mixture wasevaporated to dryness. The residue was dissolved in water andchromatographed on "Amberlite" IR120 (K⁺ form) ion exchange resin. Theeluant was concentrated and chromatographed on Dianion HP20SS resin togive the product (29) (17 mg).

νmax (KBr) 3270, 1770, 1675, 1240 and 1050 cm⁻¹ ; δppm (D₂ O) (250 MHz)4.07 (AA¹, 2H), 4.78 (s, 2H), 6.95 to 7.45 (m, 5H), 8.14 (s, 1H).

EXAMPLE 28(3RS)-3-Benzyloxycarbonylamino-1-t-butyldimethylsilyl-3-methylthio-azetidin-2-one(30)

A suspension of (22) (3.57 g) in dichloromethane (110 ml) at 0° wastreated with triethylamine (0.873 g). Propylene oxide (70 ml) was addedfollowed by benzyl chloroformate (1.64 g). The mixture was stirredovernight at room temperature, the solvent then evaporated and theresidue dissolved in ethyl acetate. The solution was washed successivelywith dilute citric acid, water, dilute sodium bicarbonate solution,water and brine, then dried (MgSO₄), filtered and the solventevaporated. Chromatography on silica gel yielded the product (30) (2.95g), mp 74°-75°, ν_(max) (CHCl₃) 3410, 1730 br, cm⁻¹ ; δppm (CDCl₃) (90MHz) 0.95 (s, 9H), 2.29 (s, 3H), 3.31 and 3.72 (ABq, 2H, J 7 Hz), 5.11(S, 2H), 5.57 (s, 1H), 7.32 (s, 5H (--Si(CH₃)₂ obscured by TMS) (Found:C 56.7; H, 7.4; N, 7.3; S, 8.2; C₁₈ H₂₈ N₂ O₃ SSi requires C, 56.8; H,7.4; N, 7.4; S, 8.4%).

EXAMPLE 29 (3RS)-3-Benzyloxycarbonyamino-3-methylthio-azetidin-2-one(31)

(30) (2.957 g) was reacted as in Example 23 to give the title compound(31) (1.846 g), as a white solid. νmax (CHCl₃) 3420, 1775 and 1730 cm⁻¹; δppm (CDCl₃) (90 MHz) 2.33 (s, 3H), 3.42 and 3.83 (ABq, 2H J 6.0 Hz),5.11 (s, 2H), 5.60 (broads, 1H), 5.82 (broad s, 1H), 7.32 (s, 5H).

EXAMPLE 30(3RS)-3-Benzyloxycarbonylamino-3-methylsulphinyl-azetidin-2-one (32)

(31) (1.836 g) was reacted as in Example 24 to give the title compound(32) (1.72 g), as a mixture of isomers (approximately 1:1) ν_(max)(Nujol) 3200, 1775, 1720, and 1020 cm⁻¹ ; δppm ((CD₃)₂ SO) (90 MHz) 2.53(s, 11/2H), 2.68 (s, 11/2H) 3.48 and 3.63 (ABq, 1H, J 7.0 Hz), 3.66 (s,1H), 5.03 (s, 2H), 7.33 (s, 5H), 8.50 (broad s, 1H, exch.), 8.63(broads, 1/2H, exch.), 9.04 (broads, 1/2H, exch.).

EXAMPLE 31 (3RS)-3-Amino-3-benzyloxycarbonylamino-azetidin-2-one (33)

(32) (1.71 g) was reacted as in Example 25 to give the title compound(33) (1.32 g) as a white solid. ν_(max) (nujol) 3400, 3260, 1760, 1735,and 1700 cm⁻¹ ; δppm ((CD₃)₂ SO) (90 MHz) 3.10 and 3.40 (ABq, 2H, J 5.0Hz), 5.01 (s, 2H), 7.33 (s, 5H), 7.72 (s, 1H, exch.), 7.91 (s, 1H,exch.).

EXAMPLE 32 (3RS)-3-Benzyloxycarbonylamino-3-formamido-azetidin-2-one(34)

(33) (1.32 g) was reacted as in Example 26 to give the title compound(34) (1.41 g) a white solid. ν_(max) (Nujol) 3330, 3225, 1775, 1730(sh), 1720, 1660 and 1645 cm⁻¹ ; δppm ((CD₃)SO) (90 MHz) 3.47 and 3.52(both s, together 2H), 5.03 (s, 2H), 7.33 (s, 5H), 7.85 to 9.00 (m, 4H,becomes m, 1H, on exch.).

EXAMPLE 33 (3RS)-Tetra-n-butylammonium3-Benzyloxycarbonylamino-3-formamido-2-oxo-azetidine-1-sulphonate (35)

A solution of (34) (526 mg) in dry dioxan (30 ml) was treated withpyridine-sulphur trioxide complex (637 mg) and stirred at roomtemperature for approximately 1 hour. The mixture was evaporated and theresidue dissolved in 0.5M KH₂ PO₄ (25 ml). The solution was extractedwith dichloromethane (×2). Tetra-n-butylammonium hydrogen sulphate (679mg) was added to the aqueous solution, followed by extraction withdichloromethane (×4). The latter organic extracts were combined, driedand evaporated to give the product (35) (1.026 g) as a white foam.ν_(max) (CHCl₃) 3400, 1780, 1730, 1700 and 1050 cm⁻¹ ; δppm ((CD₃)₂ CO)(90 MHz) 0.96 (t, 12H, J 7.0 Hz), 1.15 to 1.95 (m, 16H), 3.25 to 3.95(m, 10H), 5.10 (s, 2H), 7.34 (s, 5H) 7.66 (broads, 1H) 8.15 (s, 1H).

EXAMPLE 34(3RS)-Tetra-n-butylammonium-3-Amino-3-formamido-2-oxo-azetidine-1-Sulphonate(36)

A solution of (35) (510 mg) in methanol (20 ml) containing 10% Pd-Ccatalyst (150 mg) was hydrogenated at room temperature and atmosphericpressure for 1/2 hour. The mixture was filtered through Kieselguhr andthe filtrate evaporated to dryness, giving the product (36) (412 mg;containing a trace of solvent).

ν_(max) (CHCl₃) 3400, 1770, 1685 and 1045 cm⁻¹ ; δppm ((CD₃)₂ CO) 0.97(t, 12H, J 7 Hz), 1.20 to 1.95 (m, 16H), 2.78 (broads, 2H, exch.), 3.25to 3.60 (m, 9H), 3.72 (1/2ABq, 1H, J 6.5 Hz) 8.15 (s, 1H).

EXAMPLE 35 (3RS) Potassium3-Formamido-3-thien-2-ylacetamido-2-oxo-azetidine-1-sulphonate (37)

Thien-2-ylacetic acid (149 mg) in dry dichloromethane (20 ml) containingone drop of dimethylformamide was treated with oxalyl chloride (159 mg).The mixture was stirred for 1 hour then evaporated to dryness. Theresidue was dissolved in dry acetonitrile (5 ml) and added, dropwise, tosolution of (36) (391 mg) in dry acetonitrile (20 ml) containingpropylene oxide (1 ml) at 0° C. After stirring for 1/2 hour at 0° C.,cooling was removed. After 2 hour the mixture was evaporated to dryness.The residue was taken up in water (10 ml) containing a few drops ofacetone and passed down a column of "Amberlite" IR120(K) ion exchangeresin. Concentration of the eluant and chromatography on "Diaion" HP20SSresin eluting with water/acetone mixtures gave the product (37) (175 mg)as a white solid after freeze drying.

ν_(max) (KBr) 3490, 3270, 1775, 1675, 1245 and 1050 cm⁻¹ ; δppm (D₂ O)(90 MHz) 3.87 (s, 2H), 4.00 (s, 2H), 6.90 to 7.10 (m, 2H), 7.28 to 7.42(m, 1H), and 8.11 (s, 1H).

EXAMPLE 36 (3RS) Potassium3-Formamido-3-[2,DL-thien-2-yl-2-ureidoacetamido]-2-oxo-azetidine-1-sulphonate(38)

2-Thien-2-yl-2-ureido-acetic acid (308 mg) was suspended in dryacetonitrile (5 ml) under argon at 0° C., and treated with thionylchloride (447 mg). After 5 minutes, dry ether (10 ml) was added and themixture stirred for a further 10 minutes. The solid was filtered offunder argon and dried in vacuo. The dried solid was added to a solutionof (36) (347 mg) in dry acetonitrile (10 ml) containing propylene oxide(2 ml) at 0° C. After stirring at 0° C. for 1 hour, the mixture wasallowed to warm to room temperature and stirred for a further 1 hour.The mixture was evaporated to dryness and the residue taken up in water(some insoluble matter discarded). Chromatography on "Amberlite"IR120(K) ion exchange resin followed by "Diaion" HP20SS andlyophilization gave the product (38) (163 mg) as a white amorphus solid.ν_(max) (KBr) 3460, 3360, 1775, 1670, 1610 sh, 1245, and 1050 cm⁻¹ ;δppm ((CD₃)₂ so) (250 MHz) 3.50 to 3.75 (m, 2H), 5.55 to 5.70 (m, 1H,simplifies on irradiation at ˜6.72 ppm), 5.75 (S, 2H, exch. D₂ O), 6.66to 6.80 (m, 1H), 6.90 to 7.02 (m, 2H), 7.36 to 7.47 (m, 1H), 8.00 (s,2/3H), 8.18 (d, 1/6H, J 11 Hz, becomes s on exch.), 8.31 (d, 1/6H, J 11Hz, becomes s on exch.), 9.05 and 9.07 (both d, together 1/3H, J 11 Hz,exch. D₂ O), 9.20 (s, 2/3H, exch. D₂ O), 9.35 and 9.38 (boths, together2/3H, exch. D₂ O), 9.68 and 9.74 (both s, together 1/3H, exch. D₂ O).

EXAMPLE 37(3RS)-1-t-Butyldimethylsilyl-3-methylthio-3-[2-(p-nitrobenzyloxycarbonyl)-2-thien-3-ylacetamido]-azetidin-2-one(39)

A solution of (23) (418 mg) in dry dichloromethane (10 ml) containingtriethylamine (222 mg) at 0° C. was treated with a solution of2-(p-nitrobenzyloxycarbonyl)-2-thien-3-ylacetylchloride (407 mg) in drydichloromethane (5 ml). The mixture was stirred at 0° C. for 15 minutes,then allowed to warm to room temperature. After 1 hour the mixture waswashed successively with sat.NaHCO₃, water, dilute HCl, water and brine.The organic phase was dried (MgSO₄), filtered and evaporated.Chromatography of the residue on silica gel gave the product (39) (496mg) as a foam.

ν_(max) (CHCl₃) 3390, 1745, 1685, 1525 and 1350 cm⁻¹ ; δppm (CDCl₃) (90MHz) 0.97 (s, 9H), 2.18 and 2.21 (boths, together 3H), 3.31 and 3.73and, 3.33 and 3.75 (both ABq, together 2H, J 7 Hz), 4.79 and 4.81 (boths, together 1H), 5.31 (s, 2H), 7.01 (s, 1H, exch. D₂ O), 7.10 to 7.60(m, 5H), 8.22 (s, 2H, J 9 Hz), (--Si(CH₃)₂ obscured by TMS).

EXAMPLE 38(3RS)-3-Methylthio-3-[2-(p-nitrobenzyloxycarbonyl)-2-thien-3-ylacetamido]-azetidin-2-one(40)

(39) (200 mg) was reacted as in Example 23 to give the title compound(40) (160 mg) as a white foam.

ν_(max) (CHCl₃) 3410, 1775, 1730 sh, 1690, 1525 and 1350 cm⁻¹ ; δppm(CDCl₃) (90 MHz) 2.18 and 2.22 (both s, together 3H,) 3.41 and 3.83, and3.43 and 3.80 (both ABq, together 2H, both J 6 Hz), 4.79 and 4.82 (both,together 1H), 5.29 (s, 2H), 6.01 (broad s, 1H, exch. D₂ O), 7.05 to 7.55(m, 6H) 8.18 (d, 2H, J 9 Hz).

EXAMPLE 39(3RS)-3-Methylsulphinyl-3-[2-(p-nitrobenzyloxycarbonyl)-2-thien-3-ylacetamido]-azetidin-2-one(41)

(40) (120 mg) was reacted as in Example 24 to give the title compound(41) (125 mg).

νmax (CHCl₃) 3400, 1780, 1740 sh, 1690, 1520, 1350 and 1040 cm⁻¹.

EXAMPLE 40(3RS)-3-Amino-3-[2-(p-nitrobenzyloxycarbonyl)-2-thien-3-yl-acetamido]-azetidin-2-one(42)

(41) (125 mg) was reacted as in Example 25 to give the title compound(42) (69 mg).

ν_(max) (CHCl₃) 3400, 1775, 1740 sh, 1675, 1520, and 1345 cm⁻¹ ; δppm((CD₃)₂ SO) (90 MHz) 2.65 (broad s, 2H, exch. D₂ O), 3.11 and 3.33 (ABq,2H, J 6 Hz), 5.03 (s, 1H), 5.28 and 5.30 (both s, together 2H), 7.03 to7.25 (m, 1H), 7.34 to 7.70 (m, 4H), 7.92 and 7.98 (both s, together 1H,exch. D₂ O), 8.18 (d, 2H, J 9 Hz), 8.73 and 8.78 (both s, together 1H,exch. D₂ O).

EXAMPLE 41(3RS)-3-Formamido-3-[2-(p-nitrobenzyloxycarbonyl)-2-thien-3-ylacetamido]-azetidin-2-one(43)

The amine (42) (490 mg) in dry dichloromethane was cooled to 0° C. andtreated with pyridine (211 mg) followed by formic-acetic anhydride (117mg). The mixture was stirred at 0° C. for 5 minutes then allowed to warmto room temperature. After 1/2 hour the solvent was evaporated and theresidue dried in vacuo. The solid was triturated with dry ether,filtered off, and washed with more ether before drying in vacuo to givethe product (43) (510 mg) as a white solid.

ν_(max) (NUJOL) 3250 br, 1780 sh, 1760, 1680 sh, 1655 and 1345 cm⁻¹.

EXAMPLE 42 (3RS)-Potassium3-Formamido-3-[2-p-nitrobenzyloxycarbonyl)-2-thien-3-ylacetamido]-2-oxo-azetidine-1-sulphonate(44)

The β-lactam (43) (100 mg) was suspended in dry dioxan (6 ml) andtreated with pyridine-sulphur trioxide (37 mg). The mixture was stirredat room temperature for 40 h, then the solvent was evaporated. Theresidue was taken up in water containing a small quantity of KH₂ PO₄(--some insoluble solids were discarded), and chromatographed on"Amberlite" IR120(K) ion exchange resin followed by "Diaion" HP20SS.Lyophilization gave the product (44) (30 mg) as a white amorphus solid.

ν_(max) (KBr) 3460 sh, 3300, 1775, 1745 sh, 1680, 1350 and 1050 cm⁻¹ ;δppm (D₂ O) (250 MHz) 3.92 (d, 1H, J 6.7 Hz), 4.01 and 4.02 (both d,together 1H, both J 6.7 Hz), 5.26 to 5.45 (m, 2H), 7.08 to 7.18 (m, 1H),7.40 to 7.60 (m, 4H), 8.08 and 8.09 (both s, together 1H), 7.23 (d, 2H,J 8 Hz).

EXAMPLE 43 (3RS)-Dipotassium3-(2-carboxylate-2-thien-3-ylacetamido)-3-formamido-2-oxo-azetidine-1-sulphonate(45)

A solution of (44) (70 mg) in water (5 ml) containing 10% Pd-C (35 mg)was hydrogenated at atmospheric pressure and room temperature for 1/2hour. The mixture was filtered to remove the catalyst. Chromatography ofthe filtrate on "Amberlite" IR120(K) ion exchange resin followed by"Diaion" HP20SS and lyophilization gave the product (45) (40 mg) as awhite solid.

ν_(max) (KBr) 3440, 3260, 1775, 1670, 1605 and 1050 cm⁻¹ ; δppm (D₂ O)(250 MHz) 3.98 to 4.14 (m, 2H), 4.67 and 4.69 (both s together 1H), 7.07to 7.13 (m, 1H), 7.28 to 7.36 (m, 1H), 7.40 to 7.48 (m, 1H), 8.13 and8.15 (both s, together 1H).

EXAMPLE 44 Potassium(3RS)-3-[2-Chloroacetamidothiazole-4-yl)-2-methoxyiminoacetamido]-3-formamido-2-oxo-azetidine-1-sulphonate(46)

2-(2-Chloroacetamidothiazol-4-yl)-(Z)-methoxyiminoacetyl chloride (500mg) was suspended in dry acetonitrile (20 ml) and propylene oxide (5 ml)added to give a clear solution which was cooled to -20° C. The amine(36) (677 mg) in dry acetonitrile (5 ml) was added. After 20 minutes thesolvents were evaporated and the residue dried in vacuo. The crudeproduct was dissolved in dry acetone (2 ml) and potassiumnonafluorobutane sulfonate (509 mg) added in the minimum volume ofacetone. The slurry was diluted with an equal volume of ether andfiltered to give the crude potassium salt. Chromatography on "Diaion"HP20SS resin eluting with water and then 71/2% acetone; wateer gave thepure product (46) (501 mg) after freeze drying ν_(max) (KBr) 3450 br,3240 br, 1775, 1675 br and, 1045 cm⁻¹ ; δppm (D₂ O) (250 MHz) 4.01 (s,3H), 4.13 and 4.20 (2H, ABq, J 6.3 Hz), 4.42 (2H, s), 7.48 (1H, s), and8.20 (1H, s).

EXAMPLE 45 Potassium(3RS)-3-[2-(2-Aminothiazol-4-yl)-2-methoxy-iminoacetamido]-3-formamido-2-oxo-azetidine-1-sulphonate(47).

The lactam (46) (100 mg) was dissolved in water (1.5 ml) at 5° C. andsodium N-methyldithiocarbamate (39 mg) added. The mixture was stirred atroom temperature for 11/2 hour, washed with ethyl acetate andevaporated. Chromatography on "Diaion" HP20SS resin eluting with waterand freeze drying of the relevant fractions afforded (47) (46 mg).ν_(max) (KBr)3420br, 3320br, 1775, 1665, 1620sh, and 1045 cm⁻¹ ; δppm(D₂ O) (250 MHz) 3.90 (3H, s), 4.09 (2H, s), 6.9 (1H, s), 8.15 (1H, s).

EXAMPLE 46 3-Hydroxy-2-phthalimido-N-benzyloxybutyramide (49)

Phthalimido threonine (48) (52.40 g) and --O--benzylhydroxylaminehydrochloride (47.62 g) were suspended in water (800 ml) and the pH ofthe solution adjusted to 4.5 (3N-NaOH), followed by the addition ofN,N-dimethylformamide (200 ml). To the resulting solution was added asolution of 1-(3-dimethylaminopropyl-3-ethylcarbodiimide hydrochloride(44.30 g) in water (350 ml) whilst keeping the solution stirred andmaintaining pH at 4.5 using 5N-HCl. Stirring was continued at that pHfor 1 hour after addition was complete. The mixture was then extractedwith ethyl acetate (4×350 ml), and the combined organic layers washedsequentially with 1N-citric acid (200 ml), 5% aqueous sodium hydrogencarbonate (100 ml) and saturated brine (100 ml), dried (MgSO₄) andevaporated. Silica gel chromatography of the residue gave the product(49) (59.56 g), ν_(max) (CHCl₃) 3400, 1770, 1710 and 1385 cm⁻¹ ;δ(CDCl.sub. 3) 1.18 (d, J 6.5 Hz, 3H) (irradiation at 4.59 caused thissignal to collapse to a s) 4.0 br (1H, exch.), 4.52 (m, 1H) [irradiationat 1.18 caused this signal to collapse to a d (J 5 Hz)], 4.78 (d, J 5Hz, 1H), 4.87 (s, 2H), 7.2-7.5 (m, 5H), 7.6-7.9 (m, 4H), m/e 354 (M⁺),and 91 (base peak.)

EXAMPLE 47 N-Benzyloxy-2-phthalimido-3-methylsulphonyloxybutyramide (50)

Methanesulphonyl chloride (19.1 ml) was added in one portion to a cooled(ice bath), stirred solution of (49) (59.62 g) in pyridine (250 ml).After 5 minutes the mixture was allowed to gradually reach roomtemperature. After 1 hour ethyl acetate (700 ml) was added and themixture washed sequentially with water (2×500 ml), 1.67N-HCl (2×500 ml),and dilute aqueous sodium hydrogen carbonate. The organic layer wasdried (MgSO₄) and evaporated to give the product as a light yellow foam(68.74 g). ν_(max) (CHCl₃) 3250, 1780, 1715 and 1175 cm⁻¹ ; δ(CDCl₃)1.50 (d, J 6 Hz, 3H) (irradiation at 5.54 caused this signal to collapseto a s), 2.83 (s, 3H), 4.85 (d, J 8 Hz, 1H), 4.84 (s, 2H), 5.54(m, 1H),7.1-7.4 (m, 5H), 7.6- 7.9 (m, 4H), and 9.50br (1H, exch.).

EXAMPLE 48 Trans-1-Benzyloxy-4-methyl-3-phthalimidoazetidin-2-one (51)

The mesylate (50) (71.48 g) was taken up in acetone (2380 ml) under anargon atmosphere and solid potassium carbonate (68.37 g) added withstirring. The mixture was heated on an oil bath at 80° C. for 1 hour andthen cooled. The solid was filtered off and filtrate concentrated.Towards the end of evaporation some ethyl acetate was added and themixture re-concentrated, leading to the deposition of the product as awhite solid. The solid was filtered off (26.60 g) and the filtrateevaporated and purified on silica gel to give a further quantity ofproduct (6.88 g), m.p. 156° C. (from CHCl₃ --Et₂ O), ν_(max). (CHCl₃)1800, 1780, 1710 and 1395 cm⁻¹, δ(CDCl₃) 1.25 (d, J 6 Hz, 3H), 4.02(dq J6 and 2 Hz, 1H) [irradiation at 1.25 and 4.73 caused this signal tocollapse a d (J 2 Hz) and a q (J 6 hz) respectively], 4.72 (d, J, 2 Hz,1H) (irradiation at 4.10 caused this signal to collapse to a s), 5.10(s, 2H), 7.2-7.6(m, 5H), and 7.6-7.9(m, 4H). (Found: C, 67.81; H, 4.73;N, 8.35. C₁₉ H₁₆ N₂ O₄ requires C, 67.85; H, 4.79; N, 8.33%).

EXAMPLE 49 Trans-1-Hydroxy-4-methyl-3-phthalimidoazetidin-2-one (52)

The O-benzyl derivative (51) (23.08 g) was taken up in THF (250 ml) andhydrogenolysed in the presence of 10% Pd/C until no starting materialremained. The solution was filtered through Kieselguhr and the filtrateevaporated to give a white solid (52) (16.63 g), m.p. 94°-96° C. (fromEtoAc--hexane), ν_(max) (KBr) 3400, 1795, 1770, 1720, and 1400 cm⁻¹,δ(CDCl₃) 1.45(d, J 6.5 Hz, 3H) (irradiation at 4.18 caused this signalto collapse to a s), 4.18 (dq, j 6.5 and 2 Hz, 1H), 4.70(d, J 2 Hz, 1H)(irradiation at 4.18 caused this signal to collapse to a s), 7.3-8.0 (m,4H), and 7.7-8.7br (1H, exch.), m/e 246(M⁺) and 187 (base peak). (Found:C, 58.28; H, 4.11; N, 11.46; M⁺ 246.0647. C₁₂ H₁₀ N₂ O₄ requires C,58.54; H, 4.09; N, 11.38%, M, 246.0681).

EXAMPLE 50 Trans-4-Methyl-3-phthalimidoazetidin-2-one (53)

A solution of the N-hydroxyazetidinone (52) (16.9 g) in methanol (480ml) was treated with 4.5M-ammonium acetate (390 ml), followed by a 30%solution of titanium trichloride (147 ml). After stirring the abovemixture for 1.5 hour the solution was concentrated in vacuo and thenneutralised by the addition of solid sodium hydrogen carbonate. Theresulting emulsion was extracted with ethyl acetate (×6) and thecombined organic extracts dried (MgSO₄) and evaporated to give a creamsolid (11.6 g), m.p. 214°-216° C. (from CHCl₃ --Et₂ O), ν_(max). (KBr)3320, 2460, 1795, 1780, 1770, 1725, and 1705 cm⁻¹, δ[(CD₃)SO] 1.29 (d, J6 Hz, 3H), 4.04 (dq, J6 and 2 Hz, 1H), 4.80 (d, J 2 Hz, 1H), 7.94 (s,4H), and 8.48br(1H, exch.) (Found: C, 62.60; H, 4.44; N, 12.28. C₁₂ H₁₀N₂ O₃ requires C, 62.61; H, 4.38; N, 12.17%).

EXAMPLE 51 Trans-1-(tert-Butyldimethyl)silyl-4-methyl-3-phthalimidoazetidin-2-one (54)

A solution of the azetidinone (53) (12.12 g) and tert-butyl dimethylsilyl chloride (8.77 g) in N,N-dimethyl formamide (120 ml) was cooled inan ice-bath and triethylamine (8.07 ml) added in portions. The solutionwas stirred at that temperature for 0.5 hour and then at roomtemperature for 3 hour. Ethyl acetate (600 ml) was added and theresulting mixture washed with ice-cold water (4×300 ml) followed by 0.5Mcitric acid (3×300 ml). The organic solution was dried (MgSO₄) andevaporated to give a residue which was chromatographed on silica gelgiving the title compound (54) as a white solid (11.88 g), m.p. 165° C.(From EtOAc--Hexane), ν_(max). (KBr) 1775, 1745, 1720, 1390, 1180, and710 cm⁻¹, δ[(CD₃)₂ SO|(CD₃)₂ CO] 0.30 (s, 6H), 1.04 (s, 9H), 1.45(d, J 6Hz, 3H), 4.19 (dq, J 6 and 3 Hz, 1H), 4.89 (d, J 3 Hz, 1H) and 7.92 (s,4H). (Found; C, 62.77; H, 6.82; N, 8.00. C₁₈ H₂₄ N₂ O₃ Si requires C,62.76; H, 7.02; N, 8.13%).

EXAMPLE 52Trans-3-Amino-1-(tert-butyldimethyl)silyl-4-methylazetidin-2-one (55)

The azetidinone (54) (11.88 g) in spectrograde chloroform (190 ml) wastreated with N-methylhydrazine (4 ml) in the dark for 50 hour at roomtemperature. The reaction mixture was filtered and the filtrateevaporated to give a yellow syrup (55) (5.65 g), ν_(max). (CHCl₃) 3370,1735, 1725, and 1315 cm⁻¹, δ(CDCl₃) 0.25 (s, 6H), 0.97 (s, 9H), 1.38 (d,J 6 Hz, 3H), 1.85br (2H), 3.43 (dq, J 6 and 2.5 Hz, 1H), and 3.67 (d, J2.5 Hz, 1H).

EXAMPLE 53Trans-1-(tert-Butyldimethyl)silyl-4-methyl-3-(4-nitrobenzylideneamino)azetidin-2-one(56)

A solution of 4-nitrobenzaldehyde (56) (4.00 g) in dry toluene (50 ml)was added to a solution of the azetidin one (55) (5.65 g) in dry toluene(100 ml) and the resulting solution stirred overnight in the presence of4A molecular sieves. The reaction mixture was then filtered and filtrateevaporated to give a yellow syrup which was taken up in a little ethylacetate. The solution was cooled in an ice-bath and hexane added to givethe product (56) as a cream solid (7.60 g), m.p. 104° C. (fromEtoAc--hexane), ν_(max). (KBr) 1735, 1635, 1600, 1520, and 1340 cm⁻¹,δ(CDCl₃)0.30 (s, 6H), 1.00 (s, 9H), 1.48 (d, J 6.5 Hz, 3H) (irradiationat 3.90 caused this signal to collapse to a s), 3.90 (dq, J 6.5 and 2Hz, 1H) [irradiation at 4.40 caused this signal to collapse to a q (J6.5 Hz)], 4.40 (m, 1H) [irradiation at 3.90 caused this signal tocollapse to a d (J 1 Hz)], 7.90 and 8.25 (each d, J 8.5 Hz, 4H), and8.47 (d, J 1 Hz, 1H) (irradiation at 4.40 caused this signal to collapseto a s). (Found: C, 59.02; H, 7.20; N, 12.08. C₁₇ H₂₅ N₃ O₃ Si requiresC, 58.76; H, 7.25; N, 12.09%).

EXAMPLE 54(Tert-Butyldimethyl)silyl-4-methyl-3-methylthio-3-(4-nitrobenzylideneamino)azetidin-2-one(57)

A solution of DBU (3.75 ml) in dry dichloromethane (50 ml) was added toa cooled (ice-bath) solution of the Schiff base (56) (7.6 g) and methylmethanethiosulphonate (2.27 ml) in dry dichloromethane (100 ml). Afterstirring for 30 min, the reaction mixture was diluted with moredichloromethane and washed with saturated aqueous ammonium chloride,dried (MgSO₄) and evaporated to give a deep yellow solid which wasrapidly chromatographed on silica gel to give the product (57) as alight yellow solid (6.42 g), m.p. 118°-119° C. (from EtOAc--hexane);ν_(max). (KBr) 1720, 1625-1597, 1515, 1370, 1315, and 1195 cm⁻¹,δ(CDCl₃) 0.30 and 0.33 (2s, 6H), 1.00(s, 9H), 1.30 (d, J 6.5 Hz, 3H),2.14 (s, 3H), 3.90 (q, J 6.5 Hz, 1H) (irradiation at 1.30 caused thissignal to collapse to a s), 7.98 and 8.25 (each d, J 8.5 Hz, 4H), and8.83 (s, 1H). (Found: C, 54.99; H, 6.77; N, 11.02; S, 8.06. C₁₈ H₂₇ N₂O₃ S Si requires C, 54.93; H, 6.91; N, 10.68, S, 8.15%).

EXAMPLE 553-Amino-1-(tert-butyldimethyl)silyl-4-methyl-3-methylthioazetidine-2-one,p-toluene sulphonic acid salt (58)

A solution of p-toluene sulphonic acid (82 mg) in the minimum quantityof ethyl acetate was added in one portion of the Schiff base (57) (170mg) in ethyl acetate (3 ml). After 10 minutes the solvent was removed invacuo. Trituration of the residue with dry ether resulted in theformation of the product as a cream solid (63 mg); m.p. 300° C. (fromMeOH--Et₂ O), ν_(max). (KBr) 2930, 2720, 1745, 1600, 1545, 1320, 1230,1195, 1170, 1130, 1035, and 1010 cm⁻¹, δ[(CD₃)₂ SO] 1.20 and 1.25 (eachs, 6H), 1.41 (d, J 6.5 Hz, 3H), 2.34 and 2.41 (each s, 6H), 3.97 (q, J6.5 Hz, 1H), 7.28 and 7.69 (each d, J 8 Hz, 4H), and 8.7-9.8br (3H,exch). (Found: C, 50.10; H, 7.23; N, 6.72; S, 14.84 C₁₈ H₃₂ N₂ O₄ S₂ Sirequires C, 49.97; H, 7.45; N, 6.47; S, 14.82%).

EXAMPLE 56(Tert-Butyldimethyl)silyl-3-[2-(4-ethyl-2,3-dioxopiperazine-1-carbonylamino)-2-phenylacetamido]-4-methyl-3-methylthioazetidin-2-one(59)

A solution of the tosylate (58) (680 mg) in dry dichloromethanecontaining pyridine (250 mg) was cooled in an ice-bath and treated witha solution of2-(4-ethyl-2,3-dioxopiperazine-1-carbonylamino)-2-phenylacetylchloride(750 mg) in dry dichloromethane for 30 minutes. The reaction mixture waswashed successively with dilute HCl, saturated aqueous sodium hydrogencarbonate, and brine, then dried (MgSO₄), filtered, and the filtrateevaporated. The residue was chromatographed on silica gel to give theproduct (59) (420 mg) as a mixture of diastereoisomers; ν_(max). (CHCl₃)3400, 3280, 1740, 1720, and 1690 cm⁻¹, δ(CDCl₃) 0.17, 0.2, 0.21, 0.23,and 0.24 (each s, together 6H), 0.95 and 0.97 (each s, together 9H),1.05-1.29 (complex m, together 6H), 1.84, 1.86, 2.22 and 2.23 (each s,together 3H), 3.46-3.64 (m, 4H), 3.69 (2xq, J 6.5 Hz, together 1H),3.92-4.20 (complex m, together 2H), 5.45-5.6 (complex m, 1H)(irradiation at 9.95 caused this signal to simplify to 4xs) 6.70, 6.79,6.81 and 6.85 (each s, together 1H), 7.30-7.55 (m, together 5H),9.86-10.02 (complex m, together 1H) [irradiation at 1.16 caused thesignals at (3.92-4.20) to simplify whilst the signals centered at 3.69collapsed to (2xs)].

EXAMPLE 573[2-(4-Ethyl-2,3-dioxopiperazine-1-carbonylamino)-2-phenylacetamido]-4-methyl-3-methylthioazetidin-2-one(60)

To a cooled (-20° C.) solution of the N-silylazetidinone (59) (193 mg)in tetrahydrofuran (5 ml) was added a solution of glacial acetic acid(23 mg) and tetra-N-butylammonium fluoride (119 mg) in tetrahydrofuran(2 ml) with stirring. After 15 minutes the mixture was poured into ethylacetate (40 ml) and washed in turn with 5% citric acid and saturatedbrine, dried (MgSO₄) and evaporated to give a cream solid.Chromatography on silica gel gave the product (60) (78 mg) as anoff-white solid, ν_(max). (nujol) 3500, 3250, 1760, 1710, and 1670 cm⁻¹,δ[(CD₃)₂ SO] 0.84, 0.97, 1.13 and 1.17 (each d, J 6.5 Hz, together 3H),(irradiation at 3.56 caused the signals centered at 0.84 and 0.97 tocollapse to 2xs), 1.07(t, J 7 Hz, 3H) (irradiation at 3.46 caused thissignal to collapse to a s), 1.81, 1.87, and 2.08 (each s, together 3H),3.46 (q, J 7. Hz, 2H), 3.59-4.00 (complex m, together 5H), 5.55-5.70(complex m, together 1H) (D₂ O exchange caused this set of signals toresolve into 2 broad s centered at 5.53 and 5.56), 7.25-7.58 (m, 5H),8.30, 8.36, and 8.42br (each s, together 1H, exch.), 9.22 br (s, 1H,exch.), and 9.70-9.95 (m, together 1H, exch).

EXAMPLE 583[2-(4-Ethyl-2,3-dioxopiperazine-1-carbonylamino)-2-phenylacetamido]-4-methyl-3-methylsulphinylazetidin-2-one(61)

The azetidinone (60) (250 mg) in dry dioxan (10 ml) was treated with a(5.07% w/v) solution of peracetic acid in acetic acid (0.69 ml) for 1.5hour. The solvent was then evaporated in vacuo, the complete removal ofacidic residues being ensured. Silica gel chromatography of the residuegave the title compound as a pale-white solid (149 mg), ν_(max). (Nujol)3300, 1760, 1710, and 1670 cm⁻¹, δ[(CD₃)₂ SO] 0.65, 0.93, 1.16 and 1.19(each d, J 6.5 Hz, together 3H), 1.07 (t, J 7 Hz, 3H), 1.99, 2.14, 2.39,2.64 and 2.68 (each s, together 3H), 3.37 (q, J 7 Hz, 2H), 3.47-3.52 (m,2H), 3.79-3.92 (m, 2H), 3.92-4.10 (complex m, together 1H), [5.45-5.60(complex m) and 5.86 (d, J 7 Hz), together 1H], 7.27-7.55 (m, 5H), 8.63and 8.74 br (each s, together 1H, exch), 9.14 and 9.35 br (each s,together 1H, exch.), and 9.65-10.00 (complex m, together 1H, exch).

EXAMPLE 593-Amino-3[2-(4-ethyl-2,3-dioxopiperazine-1-carbonylamino)-2-phenylacetamido]-4-methylazetidin-2-one(62)

The sulphoxide (61) (145 mg) in dioxan (5 ml) was treated with ammonia(21 ml) overnight at room temperature. The solvent was then evaporatedand the residue chromatographed on silica gel to give the product (62)as a white solid (95 mg), ν_(max). (CHCl₃) 3400, 3280, 1770, 1715 and1690 cm⁻¹, δ (CDCl₃) 0.87, 0.90, 1.10 and 1.14 (each d, J 6 Hz, together3H), 1.20 (t, J 7 Hz, 3H), 1.6-2.9 br (2H, exch.), 3.40-3.65 (m, 4H)(irradiation at 0.90 caused this signal to simplify), 3.85 (2xq, J 7 Hz,together 1H) (irradiation at 0.87 or 1.10 caused one of the abovesignals to collapse to a s), 3.95-4.13(m, 2H), 5.45(2xd, J 7 Hz,together 1H, collapses to 2 xs on exch), 6.50, 6.58, 6.63, and 6.72 br(each s, together 1H, exch.), 7.25-7.56 (m, 5H), 7.62, 7.76, 7.90, and8.06 br (each s, 1H, exch.), and 9.90 (2xd, J 7 Hz, together 1H, exch.).

EXAMPLE 603[2-(4-Ethyl-2,3-dioxopiperazine-1-carbonylamino)-2-phenylacetamido]-3-formamido-4-methylazatidin-2-one(63)

A solution of the amine (62) (87 mg) and pyridine (33 mg) in drydichloromethane (2 ml) was treated with formic acetic anhydride (40 mg)for 24 hour after which time the solvent was removed in vacuo. Drydioxan was added and solution re-evaporated (×3). Silica gel columnchromatography of the residue gave the title compound (63) (80 mg) as awhite powder, ν_(max). (Nujol) 3500, 3250, 1770, 1710, 1670, and 1500cm⁻¹, δ[(CD₃)₂ CO] 0.88, 0.96, 1.00 and 1.03 (each d, J 6.5 Hz, together3H) (irradiation at 4.00 caused the signals centered at 0.88 and 0.96 tocollapse to 2 x s), 1.16 (t, J 7 Hz, 3H), 3.49(q, J 7. Hz, 2H),3.58-3.68 (m.2H), 3.93-4.23 (complex m, together 3H), 5.59-5.84 (complexm, together 1H) (collapses to 4 x s at 5.65, 5.69, 5.76 and 5.80 uponirradiation at 10.0), 7.25-7.80 (complex m, together 6H) (simplifies onexchange with D₂ O to a m at 7.25-7.56), 7.97-8.86 (complex m, together3H) (simplifies to 4xs at 8.03, 8.11, 8.24, and 8.48 on exch.),9.90-10.05 (m, 1H, exch).

EXAMPLE 61 Potassium3[2-(4-Ethyl-2,3-dioxopiperazine-1-carbonylamino)-2-phenylacetamido]-3-formamido-4-methyl-2-oxo-azetidine-1-sulphonate(64)

The azetidinone (63) (110 mg) and sulphur trioxide-pyridine complex (200mg) in dry dioxan (8.5 ml) were stirred for 4 days and then evaporatedto dryness. The residue was taken up in a little water, passed down acolumn of IR120 (K⁺ form) ion exchange resin. The eluant wasconcentrated and purified on Diaion HP20SS resin to give the titlecompound (64) (42 mg) ν_(max). (KBr) 3500, 3300, 1775, 1710, 1685, and1045 cm⁻¹, δ(D₂ O) 1.0-1.3 (complex m, 6H), 3.50 (q, J 7 Hz, 2H)(irradiation at 1.20 caused this signal to collapse to a s), 3.6-3.8 (m,2H), 3.9-4.1 (m, 2H), 4.2-4.5 (complex m, together 1H) (irradiation at1.20 caused this signal to collapse to 3 x s at 4.26, 4.32 and 4.40),5.4-5.6 (m, 1H) (irradiation at 9.83 caused this signal to simplify to 2x s at 5.50 and 5.52), 7.4-7.6 (m, 5H), 8.07, 8.13 and 8.25 (each s,together 1H), and 9.7-9.9 (m, 1H).

DEMONSTRATION OF EFFECTIVENESS

In a standard microtitre (MIC) test, the compound of Example 14 gave thefollowing data:

    ______________________________________                                        Organism         MIC(μg/ml)                                                ______________________________________                                        E. coli JT4      25                                                           E. coli NCTC 10418                                                                             12.5                                                         S. marcescens US32                                                                             12.5                                                         K. aerogenes A   3.2                                                          E. cloacae Nl    12.5                                                         P. morganii      6.4                                                          S. aureus Russell                                                                              3.2                                                          ______________________________________                                    

We claim:
 1. A compound of the Formula (I): ##STR48## or apharmaceutically acceptable base salt thereof wherein R is --SO₃ H; R¹is amino, t-butylcarbonylamino, benzyloxycarbonylamino orbenzylideneamino, or is selected from the sub-formulae (a)-(f):##STR49## wherein n is zero, one or two, m is zero, one or two; A₁ isalkyl of 1 to 6 carbon atoms, cycloalkyl of 3 to 6 carbon atoms,cycloalkenyl of 4 to 7 carbon atoms, cyclohexadienyl, phenyl,hydroxyphenyl, thienyl or pyridyl; X is a hydrogen, bromo, chloro,carboxy or a pharmaceutically acceptable ester thereof, sulpho,tetrazolyl, azido, hydroxy, acyloxy, amino, acylamino,heterocyclylamino, ureido, guanidino or acylureido group; A₂ is phenyl,2,6-dimethoxy-phenyl, 2-alkoxy-1-naphthyl, 3-arylisoxazolyl,isothiazolyl or 3-aryl-5-methyl isoxazolyl; X₁ is CH₂ OCH₂, CH₂ SCH₂ or(CH₂)_(n) ; X₂ is an oxygen or sulphur atom; A₃ is phenyl oraminothiazolyl; and A₄ is hydrogen, alkyl of 1 to 6 carbon atoms,cycloalkyl of 3 to 6 carbon atoms, arylaminocarbonyl, alkylaminocarbonylof 1 6 carbon atoms, alkanoyl of 1 to 6 carbon atoms, alkoxycarbonyl of1 to 6 carbon atoms, alkenyl of 2 to 6 carbon atoms, carboxyalkyl of 1to 6 carbon atoms, alkylsulphonyl of 1 to 6 carbon atoms ordi-alkylphosphatomethyl of 1 to 6 carbon atoms in each alkyl moiety;wherein heterocyclyl means a 5- or 6-membered heterocyclyl groupcontaining one to three heteroatoms selected from sulphur, oxygen ornitrogen, said group being optionally substituted by one, two or threesubstituents selected from hydroxy, amino, halo and alkoxy of 1 to 6carbon atoms; R⁴ is a phenyl, thienyl or phenoxy group; R⁵ is methyl;and R² and R³ are independently selected from hydrogen or a hydrocarbongroup of 1 to 18 carbon atoms.
 2. A pharmaceutical composition usefulfor treating bacterial infections in humans and animals which comprisesan antibacterially effective amount of a compound of the Formula (I):##STR50## or a pharmaceutically acceptable base salt thereof wherein Ris --SO₃ H; R¹ is amino, t-butylcarbonylamino, benzyloxycarbonylamino orbenzylideneamino, or is selected from the sub-formulae (a)-(f):##STR51## wherein n is zero, one or two, m is zero, one or two; A₁ isalkyl of 1 to 6 carbon atoms, cycloalkyl of 3 to 6 carbon atoms,cycloalkenyl of 4 to 7 carbon atoms, cyclohexadienyl, phenyl,hydroxyphenyl, thienyl or pyridyl; X is a hydrogen, bromo, chloro,carboxy or a pharmaceutically acceptable ester thereof, sulpho,tetrazolyl, azido, hydroxy, acyloxy, amino, acylamino,heterocyclylamino, ureido, guanidino or acylureido group; A₂ is phenyl,2,6-dimethoxy-phenyl, 2-alkoxy-1-naphthyl, 3-arylisoxazolyl,isothiazolyl or 3-aryl-5-methyl isoxazolyl; X₁ is CH₂ OCH₂, CH₂ SCH₂ or(CH₂)_(n) ; X₂ is an oxygen or sulphur atom; A₃ is phenyl oraminothiazolyl; and A₄ is hydrogen, alkyl of 1 to 6 carbon atoms,cycloalkyl of 3 to 6 carbon atoms, arylaminocarbonyl, alkylaminocarbonylof 1 to 6 carbon atoms, alkanoyl of 1 to 6 carbon atoms, alkoxycarbonylof 1 to 6 carbon atoms, alkenyl of 2 to 6 carbon atoms, carboxyalkyl of1 to 6 carbon atoms, alkylsulphonyl of 1 to 6 carbon atoms ordi-alkylphosphatomethyl of 1 to 6 carbon atoms in each alkyl moiety;wherein heterocyclyl means a 5- or 6-membered heterocyclyl groupcontaining one to three heteroatoms selected from sulphur, oxygen ornitrogen, said group being optionally substituted by one, two or threesubstituents selected from hydroxy, amino, halo and alkoxy of 1 to 6carbon atoms; R⁴ is a phenyl, thienyl or phenoxy group; R⁵ is methyl;and R² and R³ are independently selected from hydrogen or a hydrocarbongroup of 1 to 18 carbon atoms, in combination with a pharmaceuticallyacceptable carrier.
 3. A pharmaceutical composition useful for treatingbacterial infections in humans and animals which comprises anantibacterially effective amount of a compound of the formula (II):##STR52## or a pharmaceutically acceptable salt thereof wherein R is--SO₃ H; R⁶ is phenyl, hydroxyphenyl, cyclohexadienyl, or a 5- or6-membered heterocyclyl group containing one to three heteroatomsselected from sulphur, oxygen or nitrogen, said group being optionallysubstituted by one, two or three substituents selected from hydroxy,amino, halo and alkoxy; R¹¹ and R¹² are each hydrogen, alkyl of 1 to 6carbon atoms, halo, amino, hydroxy or alkoxy of 1 to 6 carbon atoms; andR¹³ is hydrogen, alkyl of 1 to 6 carbon atoms or benzyl, in combinationwith a pharmaceutically acceptable carrier.
 4. A method of treatingbacterial infections in humans and animals which comprises administeringto a human or animal in need thereof an antibacterially effective amountof a compound of the Formula (I): ##STR53## or a pharmaceuticallyacceptable base salt thereof wherein R is --SO₃ H; R¹ is amino,t-butylcarbonylamino, benzyloxycarbonylamino or benzylideneamino, or isselected from the sub-formulae (a)-(f): ##STR54## wherein n is zero, oneor two, m is zero, one or two; A₁ is alk of 1 to 6 carbon atoms,cycloalkyl of 3 to 6 carbon atoms, cycloalkenyl of 4 to 7 carbon atoms,cyclohexadienyl, phenyl, hydroxyphenyl, thienyl or pyridyl; X is ahydrogen, bromo, chloro, carboxy or a pharmaceutically acceptable esterthereof, sulpho, tetrazolyl, azido, hydroxy, acyloxy, amino, acylamino,heterocyclylamino, ureido, guanidino or acylureido group; A₂ is phenyl,2,6-dimethoxy-phenyl, 2-alkoxy-1-naphthyl, 3-arylisoxazolyl,isothiazolyl or 3-aryl-5-methyl isoxazolyl; X₁ is CH₂ OCH₂, CH₂ SCH₂ or(CH₂)_(n) ; X₂ is an oxygen or sulphur atom; A₃ is phenyl oraminothiazolyl; and A₄ is hydrogen, alkyl of 1 to 6 carbon atoms,cycloalkyl of 3 to 6 carbon atoms, arylaminocarbonyl, alkylaminocarbonylof 1 to 6 carbon atoms, alkanoyl of 1 to 6 carbon atoms, alkoxycarbonylof 1 to 6 carbon atoms, alkenyl of 2 to 6 carbon atoms, carboxyalkyl of1 to 6 carbon atoms, alkylsulphonyl of 1 to 6 carbon atoms ordi-alkylphosphatomethyl of 1 to 6 carbon atoms in each alkyl moiety;wherein heterocyclyl means a 5- or 6-membered heterocyclyl groupcontaining one to three heteroatoms selected from sulphur, oxygen ornitrogen, said group being optionally substituted by one, two or threesubstituents selected from hydroxy, amino, halo and alkoxy of 1 to 6carbon atoms; R⁴ is a phenyl, thienyl or phenoxy group; R⁵ is methyl;and R² and R³ are independently selected from hydrogen or a hydrocarbongroup of 1 to 18 carbon atoms, in combination with a pharmaceuticallyacceptable carrier.
 5. A method of treating bacterial infections inhumans and animals which comprises adminstering to a human or animal inneed thereof an antibacterially effective amount of a compound of theformula (II): ##STR55## or a pharmaceutically acceptable salt thereofwherein R is --SO₃ H; R⁶ is phenyl, hydroxyphenyl, cyclohexadienyl, or a5- or 6-membered heterocyclyl group containing one to three heteroatomsselected from sulphur, oxygen or nitrogen, said group being optionallysubstituted by one, two or three substituents selected from hydroxy,amino, halo and alkoxy; R¹¹ and R¹² are each hydrogen, alkyl of 1 to 6carbon atoms, halo, amino, hydroxy or alkoxy of 1 to 6 carbon atoms; andR¹³ is hydrogen, alkyl of 1 to 6 carbon atoms or benzyl, in combinationwith a pharmaceutically acceptable carrier.
 6. A compound according toclaim 1 wherein R¹ is amino, t-butoxycarbonylamino,benzyloxycarbonylamino or benzylideneamino.
 7. A compound according toclaim 1 wherein R¹ is of the sub-formulae (a)-(e): ##STR56## wherein nis zero, one or two, m is zero, one or two, A₁ is alkyl of 1 to 6 carbonatoms, cycloalkyl of 3 to 6 carbon atoms, cycloalkenyl of 4 to 7 carbonatoms, cyclohexadienyl, phenyl, hydroxyphenyl, thienyl or pyridyl; X isa hydrogen, bromo, chloro, carboxy or a pharmaceutically acceptableester thereof, sulpho, tetrazolyl, azido, hydroxy, acyloxy, amino,acylamino, heterocyclylamino, ureido, guanidino or acylureido group; A₂is phenyl, 2,6-dimethoxy-phenyl, 2-alkoxy-1-naphthyl, 3-arylisoxazolyl,isothiazolyl or 3-aryl-5-methyl isoxazolyl; X₁ is CH₂ OCH₂, CH₂ SCH₂ or(CH₂)_(n) ; X₂ is an oxygen or sulphur atom; A₃ is phenyl oraminothiazolyl; and A₄ is hydrogen, alkyl of 1 to 6 carbon atoms,cycloalkyl of 3 to 6 carbon atoms, arylaminocarbonyl, alkylaminocarbonylof 1 to 6 carbon atoms, alkanoyl of 1 to 6 carbon atoms, alkoxycarbonylof 1 to 6 carbon atoms, alkenyl of 2 to 6 carbon atoms, carboxyalkyl of1 to 6 carbon atoms, alkylsulphonyl of 1 to 6 carbon atoms ordialkylphosphatomethyl of 1 to 6 carbon atoms in each alkyl moiety;wherein heterocyclyl means a 5- or 6-membered heterocyclyl groupcontaining one to three heteroatoms selected from sulphur, oxygen ornitrogen, said group being optionally substituted by one, two or threesubstituents selected from hydroxy, amino, halo and alkoxy of 1 to 6carbon atoms; and R² and R³ are independently selected from hydrogen ora hydrocarbon group of 1 to 18 carbon atoms.
 8. A composition accordingto claim 2 wherein R¹ is amino, t-butoxycarbonylamino,benzyloxycarbonylamino or benzylideneamino.
 9. A composition accordingto claim 2 wherein R¹ is of the sub-formulae (a)-(e): ##STR57## whereinn is zero, one or two, m is zero, one or two, A₁ is alkyl of 1 to 6carbon atoms, cycloalkyl of 3 to 6 carbon atoms, cycloalkenyl of 4 to 7carbon atoms, cyclohexadienyl, phenyl, hydroxyphenyl, thienyl orpyridyl; X is a hydrogen, bromo, chloro, carboxy or a pharmaceuticallyacceptable ester thereof, sulpho, tetrazolyl, azido, hydroxy, acyloxy,amino, acylamino, heterocyclylamino, ureido, guanidino or acylureidogroup; A₂ is phenyl, 2,6-dimethoxy-phenyl, 2-alkoxy-1-naphthyl,3-arylisoxazolyl, isothiazolyl or 3-aryl-5-methyl isoxazolyl; X₁ is CH₂OCH₂, CH₂ SCH₂ or (CH₂)_(n) ; X₂ is an oxygen or sulphur atom; A₃ isphenyl or aminothiazolyl; and A₄ is hydrogen, alkyl of 1 to 6 carbonatoms, cycloalkyl of 3 to 6 carbon atoms, arylaminocarbonyl,alkylaminocarbonyl of 1 to 6 carbon atoms, alkanoyl of 1 to 6 carbonatoms, alkoxycarbonyl of 1 to 6 carbon atoms, alkenyl of 2 to 6 carbonatoms, carboxyalkyl of 1 to 6 carbon atoms, alkylsulphonyl of 1 to 6carbon atoms or dialkylphosphatomethyl of 1 to 6 carbon atoms in eachalkyl moiety; wherein heterocyclyl means a 5- or 6-membered-heterocyclylgroup containing one to three heteroatoms selected from sulphur, oxygenor nitrogen, said group being optionally substituted by one, two orthree substituents selected from hydroxy, amino, halo and alkoxy of 1 to6 carbon atoms; and R² and R³ are independently selected from hydrogenor a hydrocarbon group of 1 to 18 carbon atoms.
 10. A method accordingto claim 4 wherein R¹ is amino, t-butoxycarbonylamino,benzyloxycarbonylamino or benzylideneamino.
 11. A method according toclaim 4 wherein R¹ is of the sub-formulae (a)-(e): ##STR58## wherein nis zero, one or two, m is zero, one or two; A₁ is alkyl of 1 to 6 carbonatoms, cycloalkyl of 3 to 6 carbon atoms, cycloalkenyl of 4 to 7 carbonatoms, cyclohexadienyl, phenyl, hydroxyphenyl, thienyl or pyridyl; X isa hydrogen, bromo, chloro, carboxy or a pharmaceutically acceptableester thereof, sulpho, tetrazolyl, azido, hydroxy, acyloxy, amino,acylamino, heterocyclylamino, ureido, guanidino or acylureido group; A₂is phenyl, 2,6-dimethoxy-phenyl, 2-alkoxy-1-naphthyl, 3-arylisoxazolyl,isothiazolyl or 3-aryl-5-methyl isoxazolyl; X₁ is CH₂ OCH₂, CH₂ SCH₂ or(CH₂)_(n) ; X₂ is an oxygen or sulphur atom; A₃ is phenyl oraminothiazolyl; and A₄ is hydrogen, alkyl of 1 to 6 carbon atoms,cycloalkyl of 3 to 6 carbon atoms, arylaminocarbonyl, alkylaminocarbonylof 1 to 6 carbon atoms, alkanoyl of 1 to 6 carbon atoms, alkoxycarbonylof 1 to 6 carbon atoms, alkenyl of 2 to 6 carbon atoms, carboxyalkyl of1 to 6 carbon atoms, alkylsulphonyl of 1 to 6 carbon atoms ordi-alkylphosphatomethyl of 1 to 6 carbon atoms in each alkyl moiety;wherein heterocyclyl means a 5- or 6-membered heterocyclyl groupcontaining one to three heteroatoms selected from sulphur, oxygen ornitrogen, said group being optionally substituted by one, two or threesubstituents selected from hydroxy, amino, halo and alkoxy of 1 to 6carbon atoms; R⁴ is a phenyl, thienyl or phenoxy group; R⁵ is methyl;and R² and R³ are independently selected from hydrogen or a hydrocarbongroup of 1 to 18 carbon atoms.
 12. A compound of the formula (II):##STR59## or a pharmaceutically acceptable salt thereof wherein R is--SO₃ H; R⁶ is phenyl, hydroxyphenyl, cyclohexadienyl, or a 5- or6-membered heterocyclyl group containing one to three heteroatomsselected from sulphur, oxygen or nitrogen, said group being optionallysubstituted by one, two or three substituents selected from hydroxy,amino, halo and alkoxy; R¹¹ and R¹² are each hydrogen, alkyl of 1 to 6carbon atoms, halo, amino, hydroxy or alkoxy of 1 to 6 carbon atoms; andR¹³ is hydrogen, alkyl of 1 to 6 carbon atoms or benzyl.